The sentence in which the pronoun and the antecedent are not in agreement is option C. If the bus is late, he will be late to class. In the first clause, the subject of the sentence is the word "bus", and in the next clause, the subject changed to "he" and the pronoun he does not clearly state its antecedent.
in that paragraph, the expression Mounting evidence could be a bit confusing, but it indicates that there's been reaserch about it before, and that it all points in the same direction, the more research proving the same point means the data is convincing. The answer is D.
There are many kinds (can't name them all off the top of my head)
1. Telling someone you'll keep it a secret and then tell anyway...
2. Always being there for someone and then not
3. When you cheat on your husband/wife or someone you're in a relationship with
4. Using someone just to get some
Those are all I can think of (at the moment). But you can just pick whichever one you want.
For 90.c I think is the correct answer