根据短文内容，从下框的A---F选项中选出能概括每一段主题的最佳选项。 选项中有一项为多余选项。

                                             
Americans have learnt more about drinks than they were 20 years ago. Now, encouraged by recent studies suggesting that it can cut the risk of cancer and heart disease and slow the aging process, tea is enjoyed by more and more people. Enough fashionable tea houses are appearing to make even longtime coffee drinkers consider changing drinks.
                                
Tea is found in more places than ever. The Tea Association of the United States reports that from 1990 to 1999, yearly sales of the drink grew to $4.6 billion from $1.8 billion. “Green tea is seen by people as a ‘functional food’” — bringing health beyond food itself, says Vierhile.
                                
Recently published studies point out that only teas that come from the leaves of the plant Camellia sinensis contain health benefits. Other teas may taste good, yet they do little more than warm up the drinker. But for Camellia sinensis, the evidence is powerful. In a 1998 study, Harvard University researchers found that drinking one cup of black tea a day lowered the danger of heart disease by as much as 44 percent compared with non-tea drinkers, and other studies have suggested that the antioxidants (抗氧化剂) in these so-called real teas can also prevent cancer.
                                
One such antioxidant in green tea is ECGC, a chemical 20 times as powerful as vitamin E and 200 times as powerful as vitamin C. “When people ask me for something good and cheap they can do to reduce their cancer risk, I tell them to drink real tea,” says Mitchell Gaynor, director of medical oncology (肿瘤学) at New York City’s Strang-Cornell Cancer Prevention Center.