Which is the best thesis statement for a paper of two or three pages?

(a) more and more people are quitting smoking because it's bad for your health

(b) the main reason people are quitting smoking are that it increases the risk of lung cancer, its offensive to others and it's very expensive

(c) there are many reasons why people fail when they attempt to quit smoking

(d) smoking is a health epidemic in the united states of America and people need to realize that quitting smoking is essential to good health