To me it seems like the words "can" and "must" are relevant. People with 10goats CAN get this genie pass on the app, but it is never ruled out that that is the ONLY way they can get it, or that they MUST do it this way.

Is there not enough of a gap to allow that Walt could have taken a third, unmentioned approach? People with 10goats COULD do it that way, and what non-10goat people do is irrelevant in this specific question.

I agree C is the perfect answer. However the explanation for A on its own feels incomplete because it does not break down the phrase "relies on", which leaves unclear the liberties we can take in interpretting answers.

Reading the text, one interpretation is that we have

1. The expert's testimony, which relies on

2. a seperate entity, Illustrations.

If they are seperate entities, and the text supports that purely verbal info is hard to understand, it would seem that by the interpretation of Effectiveness as Understandability, the author/text are indicating that the testimony ALONE is in fact not effective, which could be read as Skepticism.

tldr: when one thing RELIES ON another, can they be said to be the same thing? Must the author's attitude towards one thing include all things connected to that thing? Im sure it varies but the answer seems to take this for granted.