Which description is wrong about cyclin ( )
选项：

A: It is produced at a constant rate in the cell cycle
B: The disappearance of mitosis is due to the fact that degradation is greater than synthesis
C: Due to the periodic fluctuation of CDK level, the activity of CDK changes periodically
D: The accumulation in interphase is due to the fact that the synthesis is greater than that in interphase
E: Because its production rate is constant, the activity of CDK is constant