Choose the appropriate passive form of the following sentence:

All his friends laughed at him.

He was laughed at by all his friends.

The correct answer is Option (4) - He was laughed at by all his friends.

• The subject in the active voice ("All his friends") becomes the agent in the passive voice.
• The verb "laughed" changes to "was laughed at," and the object "him" becomes the subject of the passive sentence ("He").
• The correct structure is: Subject + was/were + past participle + by + agent.