Correct Answer: Madhu will be sent away to a boarding school by them.

Solution : The correct choice is the first option .

Passive voice is the voice in which the object experiences an action rather than the person who performs the action. Hence, the object in the active sentence becomes the subject in the passive voice.

The structure of the passive voice in the case of the simple future tense is: "Singular object + will be + past participle form of the verb + prepositional phrase + 'by' followed by the agent of the action."

Therefore, the correct answer is: "Madhu will be sent away to a boarding school by them."