Parallel questions have a highly regimented theory and approach – they’re among the question types where following the curriculum yields the greatest advantage over approaching them “normally,” even if your core logical intuitions are very strong. Review these lessons. They’re important.

But in short, our job is to develop an abstract model of the stimulus’ argument, preserving the structure but not the subject matter, then take a shallow dip into the answer choices looking for structural mismatches. Usually that suffices to identify the correct answer, but sometimes we’ll need a deep dive to distinguish between the (usually just two) answer choices that remain after our shallow dip.

Our argument introduces two necessary conditions to achieve a goal, says they’re mutually exclusive, then concludes the goal won’t be achieved.

Here’s an abstract summary with slightly more detail than the one above:

Theo needs two things to achieve his goal: he needs Thing 1 to happen, and he needs Thing 2 not to happen.
But if Thing 1 happens, Thing 2 is definitely gonna happen.
So Theo is screwed.

Filing tax return on time = File
Accountant files the return = Acc
Additional documents needed = Docs

Premise 1: File → Acc and /Docs
Premise 2: Acc → Docs
Conclusion: /File

Our correct answer is allowed to swap out individual terms (like maybe File turns to Ice Cream), but it must keep this structure.

In Premise 1, “only” introduces the necessary condition, which has two terms joined by “and”.
Premise 2 has a simple “if, then” structure.
The Conclusion is marked by “Therefore”.

The answer to this particular question happens to preserve the argument’s “not” phrasing (“...and the accountant does not ask…”), so both the english summary and the diagram presented above preserve it too for ease of understanding. It’s important to note, though, that whether concepts are expressed in the positive or negative doesn’t matter in parallel questions. In other words, you can’t eliminate an answer choice just because it doesn’t include the word “not.”