If someone asks you, "What do you usually do with your QQ?'' You may say, "I just chat ." Niu Lianzhong teaches PE in a middle school and he sets up  a QQ group. However, his purpose  is not to chat or show himself. He doesn't want to do anything for fun, either. He just wants more people to know the QQ group. He hopes to help others and now he saves more than 400 people's lives. We all know there are four blood types-A, B, AB, and O. But in fact, a few people's blood types are very special . Niu is just one of them. Since he sets up his QQ group, more than 100 special-blooded people in China join in it. Now, when a patient or a hospital needs some special blood, they just call Niu for help. And Niu contacts his members of the QQ group quickly. Till now, he has donated his blood for about 20 times. Niu hopes that more people will join his group to help others. How many people does he help in all ?
Over 400 people. Around 100 people. About 50 people. 20 people.