B- Compound sentence
Definition of compound sentence: A compound sentence is a sentence that consists of two clauses.
Further Explanation:
Simple sentences only have one clause, so that isn't it.
Example: I ate the cheese.
And complex sentences have dependent and independent clause with usually a comma between them---so that is incorrect as well.
Example: When the cake is brown, take it out of the oven.
^ sounds strange alone. ^ sounds fine alone.
I hope this helped! || much love! <33