This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
[{'content': 'A 18 year old with pain and tenderness in left scrotum, and normal right scrotum, what should be the investigation done ? \nSelect and explain. \nA. B mode USG, B. Color doppler, C. CT scan, D. MRI', 'role': 'user'}, {'content': "Answer: B \nExplanation: Colour doppler should be done to look for the testicular aery pulsation as this is most probably a case of torsion testis on left side.Reference : page 1082 SRB's manual of surgery 5th edition", 'role': 'assistant'}]