3.
Your Answer is
Correct Answer is B
Explanation
The relationship between poetry and expect is investigated here, which should be a passive relationship, that is, "poetry is expected", so the past participle is used as the attributive, and B is correct.
Item A: Make this sentence have two predicate verbs, wrong.
Item C: Active form error.
Item D: The attributive clause should be that was expected, so it is wrong.