Number four tripped me up. Can we move indicator words around to fit something else? For ex.

Premise: The costs for taxpayers who fail to file their returns on time are now much higher than it would have been to file them in a timely manner.

Premise: ...since taxpayers value their earnings and peace of mind...

Conclusion: Therefore, those that might have missed the deadline will now strive to file on time.

We added therefore onto the sentence that was originally attached to," therefore, since taxpayers value their earnings and peace of mind."

I think its so important to learn the wording! I attached myself to A because I read the sitmulus and inferred that everyone who didn't miss class, automatically would've had an A. Like it was said, they could have, but the stimulus mentions nothing about A, or that perfect attendance was linked to it. "All students who got a bad grade had imperfect attendance. Don't confuse that with all students with imperfect attendance got a bad grade." Kind of a mind game, but once I understood, it really cleared up confusion.