Answer:
Last answer
Explanation:
The first 3 answers can be thrown out by process of elimination.
Answer 1 can't be right because no human has been on Mars.
Answer 2 can't be right because the space shuttle launch came after the last humans were on the moon.
Answer 3 can't be right because again the space shuttle didn't come around until long after the last human was on the moon.
So the only possible answer has to be the last.