The answers to your question should be options C and A.
This is because a complex sentence is supposed to have one dependent clause, and one independent clause.
Option C - The independent clause is "I like to read adventure stories" and the dependent clause is "but not poems".
Option A - The independent clause is "I like to read adventure stories", and the dependent clause is "not poems".
The independent clause is the part of the sentence that can be a full sentence itself. The dependent clause is the part of the sentence that is extra information next to the independent clause.