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

You never hear of a happy billionaire.

A happy billionaire is never heard of.

The correct option that expresses the given sentence in passive voice is A happy billionaire is never heard of.

The other options are incorrect because:

• A happy billionaire never heard of is in the active voice.
• A happy billionaire is never heard by you is grammatically incorrect. The subject of the sentence is "A happy billionaire," which is not a person. Therefore, the verb "heard" cannot be followed by the preposition "by."
• No one hears a happy billionaire is in the active voice, and it does not emphasize the recipient of the action.