To start with, Rosaline, I would NOT recommend diagramming this question, because it is not a good example of conditional ("if...then") reasoning, despite the presence of the word "must" in the stimulus. The author isn't saying "If X is true, then the play must have been written during these years", and although we could perhaps analyze it in that way, doing so would be more effort than it's worth. Don't try to force arguments into conditional frameworks, but only go there if they are obviously and easily built in that way. We typically don't diagram anything other than true conditional arguments, other than an occasional Formal Logic question or a particularly confusing Causal argument with a domino-effect chain of causes and effects.
Instead, focus on the conclusion, which is that the play must have been written between 1431 and 1471. The evidence is that the coin mentioned in the play wasn't circulate until 1431, which is supposed to set the earliest date it could have been written, and the King who died in 1471 was supposedly alive when it was written (because the dedication said he was), which supposedly sets the latest date.
To weaken, then, we need to find an answer that raises some doubts about that conclusion. Anything that allows the play to have been written either before 1431 or after 1471 would do the job! I wouldn't suggest that you prephrase anything more specific than that, so as not to overly constrain yourself, but some answers that might do the job could be:
News of the King's death took a few years to spread to some areas, including where the play's author lived and worked.
The real Rose Noble coin was named after an imaginary coin of the same name from the play.
The first answer would allow the play to have been written in some year after the king died while still saying he was alive; the second would allow the play to have been written earlier, perhaps decades earlier, than 1431, when the real coin was named after the one in the play. To me, that's a bit like the space shuttle Enterprise being named after the ship in Star Trek, so not that far-fetched.
To sum up, here's the process: 1) identify the conclusion; 2) prephrase something that makes that conclusion seem less likely, even a little bit; 3) look for an answer that does what you prephrased.
Answer E does the trick here, because it means that the play could have been written as early as 1428, because while the coin hadn't yet been circulated, everyone was already talking about it in advance. Circulation of the coin no longer establishes the earliest date for the play being written!
Answer C does nothing to change the date range. So what that they stopped minting and circulating the coin in 1468? Does that mean the play could have been written before 1431, or after 1471? It has no impact whatever on the date for the play's writing! We still have to deal with the date range established by the premises.
I hope that helps!
Adam M. Tyson
PowerScore LSAT, GRE, ACT and SAT Instructor
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