While eliminating answer choices for strengthening questions, I have caught myself thinking, "this answer choice is the necessary assumption; it's too obvious for a strengthener." Yet, in fact, NA are one of the most effective ways to strengthen an argument!

However, I have also found myself choosing an answer choice for NA questions that calls out an assumption that would weaken an argument. Necessary assumptions don't merely weaken an argument when negated, they disprove an argument when negated.

So, in short, granting NA assumptions can strengthen an argument, and answer choices that merely weaken an argument can't really be the necessary assumption.

Interesting pattern in my thinking I've identified that helps me understand the relative strength of necessary assumptions in comparison to other assumptions. Understanding the NA as the bare minimum of what must be granted for the argument to make sense didn't capture this relationship to other question types for me at first.

That is all.