The correct answer is B. I was promised a present by my uncle.
A. A present was promised by my uncle to me. This is incorrect because the subject of the sentence is “my uncle” and the object of the sentence is “me.” The verb “promise” takes a direct object, so the sentence should read “My uncle promised me a present.”
C. I had been promised a present by my uncle. This is incorrect because the past perfect tense is used to describe an action that happened before another action in the past. In this sentence, there is no other action in the past that the action of being promised a present could be happening before.
D. I was promised by my uncle a present. This is incorrect because the preposition “by” is used to indicate the agent of an action. In this sentence, the agent of the action is “my uncle,” so the sentence should read “My uncle promised me a present.”