This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Anatomy
[{'content': 'In high risk population , HCC is best detected by \nSelect and explain. \nA. USG, B. CT, C. MRI, D. PET scan', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Diagnosis Focal lesion 1-2 cm: Two imaging techniques with aerial hypervascularization and venous wash out Focal lesion> 2cm: One imaging technique with aerial hypervascularization and venous washout Techniques to be considered : Dynamic CT and MRI Screening is based on regular ultrasound scanning in high risk population Biopsy proof of HCC is not required Ref: Sabiston 20th edition 1458-1463', 'role': 'assistant'}]