This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Venous Disorders, Subject name: Surgery
[{'content': 'DVT, investigation of choice is: \nSelect and explain. \nA. Duplex scan, B. Plethysmography, C. Venography, D. X-ray', 'role': 'user'}, {'content': 'Answer: A \nExplanation: * USG- Anatomical delineation* Doppler- To assess vascular flow* Duplex scan - Combination of anatomical delineation and vascular flow assessment.* Duplex scan is the IOC for diagnosis of DVT and varicose veins.', 'role': 'assistant'}]