Context: I remember I got it for my birthday as I was going on an overnight trip with Scouts . I remember one of the cub scout leaders was really tired all the time , and on the bus on the way home he slept with his head on the shoulder of one of the other cub scout leaders . He had curly hair . My parents told me after they picked me up that that was probably the last time I 'd see him , because he was dying of AIDS .

Question: Why do you think he needed to sleep at that time ?
Options:
0. The bus ride was long and he was tired
1. AIDS causes immune deficiency making someone feel tired and fatigued regularly
2. He probably wanted to have a nap to pass the time
3. He probably had not slept well while at the scouts retreat
Answer: 1