Question

a fable about a lion and a mouse teaches the lesson \even the smallest friends can make a big difference.\ this is an example of:
main idea
theme
supporting detail
central idea

Explanation:

The theme of a story is the underlying message or lesson it conveys. The fable's lesson “Even the smallest friends can make a big difference” is a broad message, which fits the definition of a theme. Main idea and central idea are more about the main point of the story's content, and a supporting detail is evidence for the main idea, not a lesson.

Answer:

B. Theme