Read the article and select the best answer. Article: Can we make animals work for us? Some scientists think that one day we can teach animals to do a lot of things for people. They say that in a film or on TV you may see elephants, monkeys, dogs or some other animals doing a lot of things. If you watch carefully, you may find those animals are always given a little food to eat after they have done something. Scientists say that people can teach many different animals to do some easy work if they know they will get something to eat. We all know elephants can carry large logs and dogs can look after houses. And we can even teach animals to work in factories. In America, for example, people use apes to help make cars. Scientists think that those big monkeys may, one day, drive trains. Now people are trying to let them do something just like man. Question: At present people are letting elephants do some _ work. Options: A: difficult B: heavy C: light D: busy
A:
B