Explanation

Reading the question: The first sentence is the conclusion. The evidence is quirky. Supposedly, the pyramid structure reveals a calendar mentality because it has (91 x 4) + 1 = 365 steps. The ideal strengthener of the argument will strengthen the link between this wacky evidence and the conclusion. It might discuss how we have established in other cases that pyramids in this culture are always built to reflect science. It might describe how the stairs are further broken into 28-day or 30-day chunks by color, or how each of the four stairways appears to represent a different season. Regardless, optimally, it will be about the pyramid and the pyramid's connection as evidence. We have our filter.

Answer choice (A) is about the pyramid, but it doesn't connect well to the calendar. Choice (B) could be taken as a weaknener, so we eliminate (B). (C) is a mild strengthener, but not an ideal one - it doesn't match our filter. Choice (D) is like (A) and is out. Choice (E) confirms that the pyramid has the 91 x 4 structure and that it has a final platform at the top. Was that in doubt? We look back at the prompt, which says, "If a platform at the top is imagined." Evidently, the pyramid is not intact. Whether or not it has the imagined shape will be critical thing #1 in whether its shape is an expression of anything. So (E) address a point that is critical to the argument.

Logical proof: We can use the negation test on (E). Say that they found a model that established that the structure had not consisted of the calendar-suggestive shape? Then the argument collapses. The correct answer is (E).