A、He is the oldest author of the study. B、He is a professor researching on nutrition. C、He studies how food is beneficial to ill

Talk show host：
    Today we have good news for all our coffee drinkers around the world. A new study finds that drinking coffee can help you live longer. Researchers at the Harvard School of Public Health recently discovered that drinking between three and five cups of coffee a day may prevent certain illnesses. They found that coffee can protect against heart disease, brain diseases and suicide. Walter Willett is a nutrition researcher at Harvard and co-author of the study. Professor Willet, thank you for joining us.
Professor Willet:
    Good morning. The findings of our study extend to both caffeinated and decaffeinated coffee, or decaf, as Americans often call it.
    The health benefits come not just from the caffeine in coffee, but from the compounds in the beans. Our study was large, of about 200,000 subjects included data from three ongoing studies. Subjects in the study had to answer questions about their coffee drinking habits every four years over a 30-year period.
    We found that moderate coffee drinking was linked with a reduced risk of death from many diseases. However, we found no link between coffee drinking and cancer.
    We also considered other habits such as smoking, obesity, and how active the subjects were. We also looked at what kinds of food the subjects ate, as well as how much alcohol—and what type of alcohol—they drank.
    Our research adds to a growing body of evidence. This body of evidence finds drinking a moderate of coffee may have many health benefits, including a longer life. This is according to one of the researchers involved in the study.
    Frank Hu is senior author of the study. He is also a professor of nutrition and epidemiology. He studies how food affects illness.
    Hu adds that data from the study support that drinking a moderate amount of coffee can be part of a healthy diet. But how much and when you drink coffee is important.
    Nevertheless, our study also received doubts and criticism.
Andrew Maynard of Arizona State University claims that the health benefits documented in this new study are "small." Maynard says the study does not prove cause and effect between drinking coffee and living longer. He says the study does point to an association, or link, between drinking coffee and living longer.
    Honestly speaking, I am personally not sure how coffee is linked to certain health benefits.
    So what I can give you as the take-home message—in other words, the important thing to learn—is that if you like coffee, do not feel guilty about drinking it in moderation. If you don’t like coffee, don’t feel you have to start drinking it to be healthy. Thank you very much.
16. What do the researchers find about coffee?
17. What do we learn about the study?
18. What do we learn about Frank Hu?
19. What criticism does the study receive?