单项选择题

Scientists have learned a great deal about the kinds of food people need. They say that there are several kinds of food that people should eat every day. What are these classes of food They are 1) green vegetables of all kinds, such as string beans, peas, lettuces, and cabbages; 2) fruit, such as apples, peaches and bananas; 3) other vegetables, examples of these are beets, onions, carrots, tomatoes and so on; 4) meat of all kinds, fish and eggs; 5) milk and food made from milk, such as butter, cheese and ice-cream; 6) bread or cereal. Rice is also in this class of food.
People in different countries and different areas of the world eat different kinds of things. Scientists say that none of these differences are really important. It doesn’t matter whether food is eaten raw or cooked, canned, or frozen. It doesn’t matter if a person eats dinner at four o’clock in the afternoon or at eleven o’clock at night. The important thing, they say, is that every day a person should eat something from each of these kinds of food.
There are two problems, then, in feeding the ever-increasing number of people on earth. The first is to find some ways to feed the world population sd that no one is hungry. The second is to make sure that people everywhere have the right kinds of food to make them grow to be strong and healthy.
What green vegetable is not mentioned in the passage

A.Lettuces.
B.Peas.
C.Cabbages.
D.Spinach.