Every summer, Jennifer travels to the Amazon Rain Forest.

Is this A) compound complex

B) Complex

C) Simple

D) Compound

I think it is B, but not entirely sure

The correct answer is C. simple.

The sentence above is a simple sentence because it only has one predicate (finite verb) and that is travels. It consists only of one independent clause, thus making in a simple sentence.

A compound sentence consists of at least two independent clauses; a complex sentence has at least one subordinate clause apart from one independent clause; a compound-complex sentence has at least two independent clauses and at least one subordinate clause.