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: Unknown
[{'content': 'In tandem cartridge , the number of bullets fired are : - \nSelect and explain. \nA. One bullet, B. Two bullet, C. Three bullet, D. Multiple bullets.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Duplex or tandem cartridge\nDuplex or tandem cartridge this is used in military rifles and contains two bullets which enter the target at different points, seprated by as much as 30 cm.\nThe base of the forward bullet is notched , into which the second bullet fits closely.', 'role': 'assistant'}]