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: Medicine
[{'content': 'A 28-year-old lady has put on weight (10 kg over a period of 3 years) and has oligomenorrhoea followed by amenorrhea for 8 months. The blood pressure is 160/100 mm of Hg. Which of the following is the most appropriate investigation? \nSelect and explain. \nA. Serum electrolytes, B. Plasma cortisol, C. Plasma testosterone and ultrasound evaluation of pelvis, D. T3, T4 and TSH', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]