Select the option that expresses the given sentence in passive voice.

I laughed at the clown.

The clown was laughed at by me.

The correct passive form of the given sentence is The clown was laughed at by me.

The active voice of the sentence is I laughed at the clown. This sentence is in the simple past tense, which is used to describe an action that happened in the past. The passive voice of the sentence is formed by putting the subject of the active sentence after the verb "to be" and the past participle of the main verb. In this case, the subject of the active sentence is "I" and the main verb is "laugh." The past participle of "laugh" is "laughed." So, the passive form of the sentence is The clown was laughed at by me.

The other options are incorrect because:

• The clown was being laughed by me. is in the present progressive tense, which is used to describe an action that is happening now. The action of laughing at the clown is not something that is happening now.
• The clown is being laughed at by me. is also in the present progressive tense.
• The clown is laughed by me. is grammatically incorrect. The verb "is" is singular. The subject of the sentence is "the clown," which is plural.