That would be extremely unprofessional and it shows that you're more interested in getting a paycheck than you are about the company itself. Asking what the company does in an interview also shows that you didn't put any effort into looking into the company or what job you would be doing.
This will make you unprofessional as said by the person who answered first because you are only thinking about how much money you will recieve which will make the person hiring you think that you will put less effort in your job just to get your money.
The correct answer is D. This is due to the fact that it is the simplest and there can be no ambiguity whatsoever in conveying the meaning that you enjoy going to the library. Other sentences would not be (or would rarely be) seen in everyday conversation.
