单项选择题

Smokers who want to kick the habit might soon get help from a product that’s being tested at the University at Buffalo School of Dental Medicine: a mouth wash that makes cigarettes taste bad. It could be on the market within a year.
The anti-smoking rinse itself tastes rather pleasant. But if you light up within 6 to 8 hours of smoking it, your cigarette will taste like burnt rubber and you won’t smoke past the first puff, explains Dr. Sebastian Ciancio, director of the Center for Dental Studies at the University of Buffalo.
Ciancio is heading up a pilot study in which 10 smokers, each of whom normally smoke at least a pack of cigarettes a day, are rinsing their mouths three times daily with the anti-smoking solution. Another 10 are getting a placebo. Prior to this study, only the inventor had tested the anti-smoking rinse—a chemist who does not wish to be identified—and a few of his friends, who say it enabled them to quit smoking.
And Ciancio has no shortage of volunteers: The waiting list to participate in the study is already full. "People arc desperate," he says. If the pilot study is successful, it will be expanded.
Not only might the patented formulation deter smoking, Ciancio adds, but it also appears to reduce plaque, gingivitis, and halitosis. Manufacturing the rinse, he estimates, would cost approximately the same as conventional mouthwashes.
How many smokers are participating in the pilot study now