Task: Question Answering
Input (English): Background Paragraph: HIV , or human immunodeficiency virus, causes AIDS. AIDS stands for "acquired immune deficiency syndrome." It is a condition that causes death and does not have a known cure. AIDS usually develops 10 to 15 years after a person is first infected with HIV. The development of AIDS can be delayed with proper medicines. The delay can be well over 20 years with the right medicines. Today, individuals who acquire HIV after 50 years of age can expect to reach an average human life span. 
Story: Tom and Andy are two old friends. Tom was infected with HIV 20 years ago, and Andy has been helping him ever since. Andy is as healthy as an ox. 
Question: Which friend has a weaker immune system?
Output (English): Tom.