A. It was expected by Alexander that he should conquer the world.
B. It was expected by Alexander that he would conquer the world.
C. It was expected by Alexander that he will conquer the world.
D. It had been expected by Alexander that he would conquer the world.
Given sentence is in simple past tense and it is in active voice.
Rule :
Subject + (was/were) + V3 + Other agents
