This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
[{'content': 'In tandem caridge, the number of bullets fired is \nSelect and explain. \nA. One bullet, B. Two bullets, C. Three bullets, D. Multiple bullets', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Duplex or tandem caridge: this is used in military rifles and contains two bullets which enter the target at different points, separated by as much as 30 cm. The base of the forward bullet is notched, into which the second bullet fits closely.', 'role': 'assistant'}]