Answer:
(C) look before you leap
Explanation:
A theme is the moral or the lesson of the story.
(A) many animal around the world are dangerous is not a theme because it's not teaching me anything, so it is a opinion.
(B) all runners are very athletic is not a theme either because it doesn't teaches me anything, so it is a opinion as well.
(C) Look before you leap is a theme because it is teaching me to be careful.
(D) courage means to be brave is not a theme because it isn't even telling me a lesson even though it's saying a fact but not a lesson.