What is closest relative to hiv-1

Question

Problem:

Question 1: Which of the following is considered the closest relative to HIV-1?

1. Chimp SIV,
2. Baboon SIV,
3. Green monkey SIV,
4. Polio,
5. HIV-2

Question 2: Hooper hypothesized that HIV-1 first entered humans in which decade?

1. 1920s
2. 1930s
3. 1940s
4. 1950s
5. 1960s

Give reasoning with your answer.