Why is it important that glycogen synthase is activated when dephosphorylated, while glycogen phosphorylase is activated when phosphorylated?

• A. It increases the rate of glycogen synthesis.
• B. It allows both enzymes to be active at the same time.
• C. It enhances the binding of glucose to glycogen.
• D. It prevents futile cycles by ensuring only one enzyme is active at a time.

Answer: (D)