Select the correct Active/Passive form of the given sentence.

Mohan told his brother, “Why are you disturbing the class today?”

Mohan asked his brother why he was disturbing the class that day.

The correct active/passive form of the given sentence is Mohan asked his brother why he was disturbing the class that day.

The sentence is in the simple present tense, which is used to describe an action that happens regularly or now. The active voice of the sentence is formed by putting the subject of the sentence before the verb and removing the word "by." In this case, the subject of the sentence is "Mohan" and the verb is "ask." So, the active form of the sentence is "Mohan asked his brother why he was disturbing the class that day."

The other options are incorrect because:

• Mohan told his brother, “Why are you disturbing the class today?” This is the original sentence in the active voice.
• Mohan asked his brother why you had been disturbing the class today.” This is incorrect because the word "you" is used to refer to the person who is speaking, but Mohan is asking his brother why he is disturbing the class.
• Mohan asked his brother why was he disturbing the class that day.” This is incorrect because the verb "was" is in the past tense, but the sentence is asking a question about the present.
• Mohan told his brother why he had disturbed the class today.” This is incorrect because the verb "had disturbed" is in the past perfect tense, which is used to describe an action that happened in the past and is still relevant to the present.