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
Which is associated with G2M transition in cell cycle? 
Select and explain. 
A. Cyclin A, B. Cyclin B, C. Cyclin E, D. Cyclin D
B: Cyclin B
Answer: B: Cyclin B 
Explanation: None