[单项选择]

The following two questions are based on the following passage:
A study by a group of dentists has concluded that regular use of a certain brand of mouthwash is as effective as flossing in preventing gum disease. The mouthwash company has released a television ad suggesting that people who do not like flossing can now rely solely on mouthwash and brushing to maintain good dental health. A leading manufacturer of dental floss brought a lawsuit against the mouthwash company demanding that the advertisement be discontinued on the grounds that it is misleading.

Which of the following, if true, most supports the mouthwash company’s defense that its advertisement promotes greater public health ？（）
A. Since the dental floss company is protesting the advertisement only to protect its own economic self-interest, it cannot be seen as representing greater public health.
B. Greater public health is best served if people use both mouthwash and dental floss, a combination that has been shown to be more effective than either method used alone.
C. Many people object to flossing because it is painful and causes their gums to bleed.
D. Since, on average, people are twice as likely to use mouthwash regularly as to floss regularly, the advertisement will increase the number of people who take effective action against gum disease, a serious public health problem.
E. Gum disease has been proven to have links with the early onset of heart disease, one of the top three threats to public health in terms of mortality.