Which is the BEST way to write the two clauses as one complete sentence?
I need to take a nap. The class is not over.
A. I need to take a nap because the class is not over.
B. I need to take a nap since the class is not over.
C. I need to take a nap whenever the class is not over.
D. I need to take a nap although the class is not over.