Simile is a figure of speech that uses <em>"as"</em> and <em>"like" </em>to compare two things. It is used in comparing one thing with another thing that is of a different kind.
This tries to compare "<em>when friends can't be found"</em> to "<em>a bridge over troubled water". </em>Simile differs from metaphor because it compares two things directly by highlighting the similarities between those two things using "like" or "as".<em> </em>Metaphors actually create an implicit comparison.
Well it could be A or C 'cause brainstorming is really good but also is asking your friends about what they would enjoy in a paper. But with that said, I would go with C.