Complete Question Explanation
(See the complete passage discussion here:
viewtopic.php?f=1159&t=11221
The correct answer choice is (A).
The main point of the passage is that Denise Schmandt-Besserat argues that the tokens found near the Jordan River dating to around 4,000 B.C. evolved into abstract written language.
This idea is first briefly mentioned in the passage at the end of paragraph one. "The tokens are identified by Denise Schmandt-Besserat ... as overlooked predecessors to the written word" (lines 17-19). This idea is explored in more detail in the final paragraph of the passage. "The eventual evolution of this system [i.e. the token system] into mature writing, Schmandt-Besserat suggests, can be seen in the following example" (lines 43-45). The example that follows describes the stages of that evolution.
Answer choice (A): This is the correct answer choice. This answer best matches the main point described above regarding Schmandt-Besserat's argument/conclusion that the tokens evolved into abstract written language. Notice that abstract written language is equivalent to the "mature writing" mentioned in line 44. The best way to confirm this is that the example describing the stages of the evolution that appears at the end of the passage ends with "an abstract and flexible written form" (line 54). In other words, that was the "mature writing" mentioned earlier that the tokens eventually evolved into.
Answer choice (B): There are two problems with this answer. The biggest problem with this answer is that, while Schmandt-Besserat does theorize "that the envelopes contained official records of villagers' contributions to temple-based grain and livestock pools" (lines 30-33), this is a detail in the passage rather than the main point, which is about how the tokens evolved into mature/abstract writing. An additional reason that this answer is incorrect is that the discovery of the clay tablets does not "confirm" Schmandt-Besserat's belief as stated in this answer. She theorizes that this is what the tokens were used for, but this is just her theory and has not been confirmed/proven.
Answer choice (C): There are multiple problems with this answer. Perhaps the most obvious error is that this answer describes "the puzzlement of archeologists over the sudden appearance of sophisticated
crafts" (my emphasis). While the idea that crafts were becoming more sophisticated is mentioned in the passage (lines 35-37), this was
not the thing that puzzled archeologists according to the passage and is
not the focus of the passage. The thing that puzzled archeologists was the "seemingly sudden appearance of such abstract writing" (lines 9-11). We also don't know that the evidence was "required to resolve the puzzlement" as described in the answer.
Last but not least, the inscription-bearing envelopes containing tokens were
not discovered in modern Iraq. This is very easy to get confused because the passage begins by describing clay tablets that were discovered near present-day Iraq (lines 1-3), but these are
not the same tablets as the inscription-bearing envelopes containing tokens that were found near the Jordan River. One of the things that makes this confusing is that these inscription-bearing envelopes are also described as clay tablets (lines 22-25). (Of course, knowing that the Jordan River is not in or near Iraq makes this easier to realize.) Also, the inscription-bearing envelopes containing tokens were dated around 4,000 B.C. while the tablets discovered near present day Iraq were dated around 3,000 B.C.
Answer choice (D): The main problem with this answer, and the easiest way to eliminate it, are the words "modern languages." Nowhere in the passage are modern languages discussed, and it would be a serious mistake to assume that "mature writing" (line 44) and "abstract writing" (line 10) imply modern languages. They do not. The writing being discussed in the passage is thousands of years old and would therefore be considered ancient, which is the opposite of modern. While someone may think that ancient languages may have later evolved into modern languages, that idea is not discussed anywhere in the passage itself, so it cannot be part of the main point of the passage.
Answer choice (E): There are several problems with this answer. Like with Answer B, the word "confirms" is not accurate. The discovery of inscription-bearing envelopes containing tokens doesn't confirm any of Schmandt-Besserat's hypotheses, so that word alone makes this answer incorrect. Also, this answer misstates Schmandt-Besserat's hypothesis. Schmandt-Besserat uses the fact that the many of the token forms became more figurative to suggest that "villagers' crafts were becoming more diversified and sophisticated" (lines 36-37). "Diversified and sophisticated" does not necessarily mean more abstract. As with Answer C, the crafts are not the focus of the passage and therefore are not really relevant to the main point of the passage.
Since answer choice (A) uses the phrase "roughly" 4000 B.C., we don't need the passage itself to assert the tokens were made in 4000 B.C. specifically. The phrase "roughly" accounts for a similar degree of uncertainty as noted in the passage (some tokens before, some after) so that phrasing isn't reason enough to eliminate (A). In fact, like you mentioned, (A) is the correct answer so we definitely don't want to eliminate it! 
