Which sentence is a run-on sentence?

to gain popularity at school, fitzgerald wrote plays for the school and cast himself as the star. he also joined one of the universitys most prestigious clubs.

answer: common sense was the pamphlet that thomas paine used to convince reluctant americans to abandon the goal of reconciling with britain and to accept that independence was the only option to preserve their liberty.

i don't see any right answer. i don't know english and only math

i think the answer might compound