I like the conclusion matching method - when you don't have time to diagram each answer, and you need to make an educated guess quickly, it can be helpful.

I've gone grey!

I was unsure about this question because it seems so uncommon that the LSAT actually has a question that is ad hominem.

I think what helped me with this question is to refer to the definition of "expedient":

_

"(of an action) convenient and practical, although possibly improper or immoral."

For me, only after becoming familiar with the implied immorality of, could I clearly see that this was attacking his character. _

Knowing that the word 'expedient' implied immorality made it clearer to me that they were referring to/attacking his character.