Answer: Invest according to your risk appetite
Explanation:
The purpose of this question is to measure your risk appetite. There is therefore no right or wrong answer.
If you pick nothing, then you are very risk averse because you don't want to risk your salary on a venture with only a 20% chance of success.
If you would invest a month salary, you are not risk averse but you only have a moderate risk tolerance.
If you invest three months salary on a venture with a 20% chance of success, you have a high tolerance for risk.
If you take it a step further and invest six months salary, this shows that you have a very high risk tolerance.