Hi, Max,
It's possible that you are "overthinking" this stimulus and perhaps getting lost in unnecessary digressions. When you work a stimulus such as this, try to distill it down to its key components. You've done a good job breaking down this argument, but let me add a couple suggestions:
Start with the conclusion:
Filmgoers did not stay away from the movie because of the negative reviews.
Consider the support the film director offers:
The film opened the same weekend as did several other films that share the same audience.
The number of such viewers is small.
Now notice any possible flaws or gaps in the reasoning. The director assumes without providing justification that the limited audience size is zero sum, that more films mean a divided audience. He makes a causal argument.
Since the task is to support the director's conclusion, prephrase first by recognizing the type of information that you're looking for, second by thinking of any obvious ways to accomplish this task.
For example, here you could prephrase that you want something that will really show that it was the other movies' openings that were to blame for the poor performance and not the negative reviews. Since the argument involves a causal fallacy, you could brainstorm that you might like evidence that suggests that any time multiple such movies are released on the same weekend, performance drops for all films relative to performance of similar films on other, less crowded weekends. Etc. Etc.
In this case, answer choice B does provide support to suggest that filmgoers are not inclined to see multiple movies on the same weekend, bolstering the case that the problem was the movies rather than the reviews.
Answer choice E does not directly address the gap here or provide reasons why the other films were the problem and not the negative reviews. This answer is actually out of scope. To avoid other similar situations, try to limit assumptions you bring into LR problems. Try to recognize when you have to introduce an intermediate step between any given answer choice and the task you wish to accomplish. Further, rely on strict clarity about an argument's components and develop strong prephrasing skills to avoid falling into traps.
Please let me know how I may be of further help.
