Which sentences is a complex sentence?

Question

A. I like to watch tennis, and I like to play tennis
B. I like to watch tennis because it is entertaining
C. I like to play tennis
D. I like to watch and play tennis

Answer 1

B. I like to watch tennis because it is entertaining.

This sentence is a complex sentence because it contains an independent clause ("I like to watch tennis") and a dependent clause ("because it is entertaining"). The other options are either simple sentences or compound sentences.