Change into Passive Voice:

They made him a king.

The correct option is (B).

He was made a king by them.

Given sentence is in Past simple tense and it is in active voice, we need to change it into passive voice.

Rule :
Subject + (was / were) + V3 + Optional Agents.

Concept: Change into Passive Voice

When converting a sentence into passive voice, follow these simple steps:

1. Identify the object, subject, and verb in the active sentence.
   • In this case:
     • Subject: They
     • Verb: made
     • Object: him
2. Move the object to the beginning of the sentence.
   • Him becomes He because the pronoun changes to its subjective form in the passive voice.
3. Adjust the verb:
   • Use the verb to be in the correct tense and add the past participle of the main verb.
   • Made (past tense) becomes was made in passive voice.
4. Place the subject (from the active voice) at the end, introduced by the word "by."

Thus, They made him a king changes into He was made a king by them.