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: Pathology
[{'content': 'Which is associated with G2M transition in cell cycle? \nSelect and explain. \nA. Cyclin A, B. Cyclin B, C. Cyclin E, D. Cyclin D', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]