Mock quiz question: necessary or sufficient cause?

Bob realizes that it is his life long dream to compete in the Summer Olympics, as a runner, he thinks to himself that he is a young man (18 years old) with two legs and a dream, why wouldn't he be able to compete? Bob has no formal running training and asthma.

Question: In this scenario the fact that Bob has two legs and a dream is:

a) a necessary cause

b) a sufficient cause

c) neither

Answer: A

reason: the fact that Bob has two legs and a dream is necessary for him, or anyone to compete in a foot race, but these factors are in no way sufficient for him to actually become an olympic level competitor. sufficient causes would be record breaking speed, perfect lungs, and training.