Pick the sentence that would be the best thesis for a problem-solution essay.

A. Driving while intoxicated is a serious problem, but nothing can be done about it.
B. Driving while intoxicated is a serious problem, and the best way to solve it is to put into effect current laws.
C. Driving while intoxicated is a serious problem, and it's not clear exactly how to solve it.
D. Some people think that driving while intoxicated may be a problem, but no one should do it.