@SeanWolfe These questions are definitely difficult for me as well! I looked at it like this:

The conclusion/hypothesis states that genetics cause perfect pitch. As it is a strengthening question, we want to find an alternative hypothesis and then rule it out, thus strengthening the support.

So let's just say we are looking for a competing hypothesis that says some other factor, X, causes perfect pitch.

Perhaps X could be music training? It would totally make sense that some expensive music lessons would lead to cool musical capabilities like perfect pitch, right?

Except answer choice A undermines this hypothesis. It states that people who have relatives with perfect pitch (genetically) generally receive no more musical training than do others.

So it is not the case that X (music training) causes perfect pitch.

Thus, we have effectively identified an alternative hypothesis and then eliminated said hypothesis' credibility, strengthening the original hypothesis.

I hope this helps a bit!

@LaneyWilliams I like to look at conditionals without indicators as "if, then" statements. I find it makes identifying the sufficient and necessary conditions much easier.

For example: If you have mastered conditional logic, then you have memorized some amount of conditional indicators.

The sufficient condition being mastering conditional logic, and the necessary condition being memorization of some indicators.