"I am your classmate" will remain in present tense in indirect speech because in "Robert will say to me" reporting verb is in future.
So when reporting verb in in future or present, we do not change the tense of the reported speech.
3. Rakhi says to him, "You must come back home in time."
Rakhi tells him that he has to come come back home in time.
Rakhi tells him that he had to come come back home in time.
Rakhi tells him that he will have to come come back home in time.
Rakhi tells him that he must come come back home in time.
Answer: Option A
4. She said, " Ugh! I have hated him."
She exclaimed with disgust that she had been hated him.
She exclaimed with disgust that she had hated him.
She exclaimed with sorrow that she had hated him.
She exclaimed with disgust that I had hated him.
Answer: Option B
5. You said to her, "She has to cook food for you".
You told her that she has to cook food for you.
You told her that she had to cook food for you.
You told her that she needs to cook food for you.
You told her that she would have to cook food for you.