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

My brother has sent me a message.

A message has been sent to me by my brother.

The correct passive voice of the given sentence is A message has been sent to me by my brother.

The active voice of the sentence is My brother has sent me a message. This sentence is in the present perfect tense, which is used to describe an action that has happened in the past, but the time of the action is not specified. 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 "my brother" and the main verb is "send." The past participle of "send" is "sent." So, the passive form of the sentence is A message has been sent to me by my brother.

The other options are incorrect because:

• I have been sent a message to by my brother. is grammatically incorrect. The preposition "to" should not be placed before the word "by."
• A message have been sent to me. is grammatically incorrect. The verb "have" should be "has" because the subject of the passive sentence is singular.
• A message was sent to me by my brother. is in the simple past tense, while the original sentence is in the present perfect tense.