How will the right answer fit in terms of support and conclusion?

Only the right answer will be support that must be true if the conclusion is true. More simply, the right answer will be support for the conclusion that doesn’t bring in anything new.

Highlight the main conclusion in the passage, if there is one:

the chorus in a play is not equivalent to the narrator in a novel.

[BACKGROUND]. However, since [SUPPORT], [CONCLUSION].

You want to recognize that the conclusion is a necessary condition. The author doesn’t make any exceptions or use moderate wording like “probably” or might not be”. That means they think the support they gave is sufficient to prove their conclusion. In other words, they’re assuming that if the chorus is “sometimes not consistent”, then it’s “not equivalent to the narrator in a novel”. That’s what the right answer wants to sound like.

Map the wording of the answers to the wording of the passage:

(A) The narrator is a novel is never deceptive.

That word isn’t in the passage, and it definitely has a more specific meaning than just “not consistent”. This doesn’t map to the wording of the passage.

(B) The voice of a narrator is sometimes necessary…

The author is only comparing the chorus and a narrator, but never says either one is needed or required or “necessary” for anything.

(C) Information necessary for the audience to understand events…

…is never mentioned. This is changing the wording of the passage, which only says it’s information “about the context”. Don’t assume that means the information is “necessary”.

(D) Information introduced by a narrator in a novel can never be inconsistent…

Yes, this is exactly the strong wording you need to see to support a necessary conclusion. If narrators “can never be inconsistent”, then support that a chorus is inconsistent sometimes is enough to prove they’re “not equivalent”.

(E) …to mislead audiences…

Here’s a third answer that’s bending the meaning of what the passage actually says. There’s nothing in there about “misleading” anyone. That’s way more than you can assume just from the passage saying they’re “sometimes not consistent”.

(D) is the correct answer.