Reading ComprehensionHow do you react to the taste of different foods, like coffee or lemon? Do they have a flavor that you like? Or do they taste very strong to you? Why do people react differently to different flavors?We all know that different people have different food preferences. Researchers have discovered some reasons for these differences. Your culture and your life experience are partly responsible for your preference for certain foods. Your food preferences are also partly genetic. (Your genetic preferences are the ones that you were born with.) In order to discover people’s genetic preferences, researchers use a chemical called PROP. People taste it and respond to the taste. To some people, PROP has no flavor. The researchers classify these people as “nontasters.” To other people, the flavor of PROP is a little bitter, or sharp. These people are “tasters.” Then there are people who can’t stand the flavor of PROP. They find it to be unbearably bitter. These people are the “supertasters.” Tasters have more taste buds on their tongues than nontasters do, and supertasters have more taste buds than tasters do. This explains why supertasters are more sensitive to PROP and to the flavors in certain foods. So if you think the flavors in coffee, grapefruit juice, and broccoli are very strong, you may be a “supertaster.”
39（）The main idea of the reading is that _______.
(A) there are people who like different foods.
(B) there are cultural and genetic reasons for the differences in people’s food preferences
(C) some foods have a very strong flavor.
(D) PROPs can be used to identify different types of tastes.