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': 'Anita 15-year-old, complains of heavy periods since 2 months. O/E: wt 40 kg and BP 120/80 mmHg. All of the following investigations are indicated, except: \nSelect and explain. \nA. STSH, B. Platelet count, C. Bleeding and clotting time, D. Estradiol levels', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]