Could you tell me what he does? Otherwise your option D would be the most correct.

The correct answer is: B. what does he do Explanation: Could you tell me what does he do?: This is the correct choice because it asks for information about his profession, which matches the response "He is an engineer." Filling in the Blank: Other suitable ways to fill in the blank that would match the response "He is an engineer" include: "Could you tell me what his job is?" "Could you tell me what his profession is?" "Could you tell me what he does for a living?" These alternatives are all asking for information about his occupation, which aligns with the answer provided.

Could you tell me what he does? Note word order! Could you tell me his profession? Could you tell me what work he does? We normally specify the word 'work' in this context. Hope that helps.