Which of the Following Is the Most Effective Way to Handle

Which of the following is the most effective way to handle an illegal or inappropriate question during an interview?

A) Refuse to answer the question because it is your legal right to do so.
B) If you find the question harmless and if you want the job, go ahead and answer it.
C) Inform the interviewer that the question is illegal and threaten a lawsuit.
D) Storm out of the room in anger; after all, you wouldn't want to work for a company with such low ethics.