For a main point question, we should consider what the author is trying to accomplish by writing the passage. If the author is trying to make an argument (as our author is here), then the main point will usually be a summary of what the author is arguing for. The main point will be broad enough to capture the author's point- it will not focus on only one part or premise of the argument.
We could try to prephrase the main point along the lines of "The theory of collecting the similar, prevalent in other arts, is not appropriate for early movie shorts, as it fails to account for the way that they were intended to be displayed- and how audiences would have experienced them."
Answer choice A is a rough match for the prephrase, although it includes less background information. However, it does capture the core of the argument- that screenings should not only be early nonfiction as it lacks context.
B: While the author would agree with this- this is at most a secondary point C: The author is concerned with how the films are displayed, not their critical reception D: Like (B), the author may agree with this, but this is not what they are arguing for E: This is not supported by the passage- we are told that even if the restorations are authentic, the problem lies in the display.
