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: Gynaecology & Obstetrics
[{'content': 'A 35 years old lady presents with post coital bleeding and foul smelling discharge. The most important investigation to arrive at a diagnosis : \nSelect and explain. \nA. Endometrial aspiration, B. Dilatation and curettage, C. Endometrial biopsy, D. Cervical biopsy', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Cervical biopsy', 'role': 'assistant'}]