This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
[{'content': 'A child has Adenoidectomy done but he has effusion in middle ear. What is done next - \nSelect and explain. \nA. Grommet insertion, B. Mastoidectomy, C. Tympanoplasty, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]