The S Cyclin-CDK Complex

The S cyclin-CDK complex:

A) controls the cell cycle during the S and G₂ phases.
B) triggers initiation of DNA synthesis during the S phase.
C) prevents initiation of DNA synthesis a second time during the S and G₂ phases.
D) both controls the cell cycle during the S and G₂ phases, and triggers initiation of DNA synthesis during the S phase.
E) All of these choices are correct.