Answer:
Step-by-step explanation:
Basically, a compound sentence has 2 major clauses, both of which can stand by themselves.
The first sentence is just a single clause.
Although usually is a subordinate conjunction. In this case it is part of a subordinate clause. So B is not the answer.
C: is your answer. There are 2 major clauses connected by and. Both clauses stand alone.
D is like A.