She watched tv all evening and forgot to study for the test is that a simple, compound, complex, or compound complex

The correct answer is COMPOUND SENTENCE.

In this case there are two main verbs and two clauses that are at the same level of importance coordinated by the conjunction AND.
The clauses are:
1. She watched TV all evening
2. She forgot to study for the test
Both clauses share the sane subject and in the case of the second clause, “to study for the test” is an infinitival phrase occupying the place of a noun.