Answer and explanation:
If you are the interviewee at a job interview, you are allowed to ask the interviewer/employer questions. Those questions should show you are interested in the job and the company. They should not be too green, for example, showing your employer that you don't have any information as to what the company does. But if you choose to ask questions such as the ones in options B through D, you show your employer you are committed, already thinking of being hired and staying at company for a long time.
Option A, however, is not a good question. Asking about sick leaves and vacations before you have even been hired is a bad sign. The interviewer may regard you as a not-thoroughly-committed person whose only concerns are the benefits and so on, or they may see you as arrogant, since you seem to be assuming the job is already yours.
