Hi ero225!
Happy to address why answer choice (C) is incorrect.
That answer choice states, "Sonora is composed partly of materials that Barajas did not frequently use in the statues that she completed during her lifetime." You ask,
Is C wrong because it is actually possible to build something with different materials but have a similar appearance?
This seems generally right. It seems worth qualifying that we
don't know how the different materials might alter the matter of whether or not the statue sculpted by her apprentices looks very much like what she would have created. In my reading of answer choice (C), it initially looked like a contender for suggesting that Sonora is unlike her other works because of unique materials; if Sonora is sui generis or atypical, then perhaps this makes it difficult to assess that particular statue. In the end, though, that at best raises some uncertainty but doesn't clearly weaken the argument.
In addition, the answer choice suggests that Bajaras
did use the mentioned materials, just not frequently. So it's still possible that her apprentices could have replicated her use of those materials. Finally, answer choice (C) only indicates that the statue is "partly" made of these materials, which need not challenge the conclusion that it looks at least "very much like it would have looked."
By contrast, answer choice (A) weakens the argument by suggesting the 3 sketches are inadequate. Her apprentices only relied on 3 sketches to create Sonora. But if Bajaras's usual process involved going through dozens of preliminary sketches before getting to the final one, then drawing on only 3 sketches seems inadequate to reach the conclusion that Sonora looks "very much like it would have looked" if Bajaras had created it.
