In the presence of high glucose levels, how does the activity of adenylate cyclase affect cAMP levels and the activity of the lac operon?

• A. It increases cAMP levels, activating the lac operon.
• B. It decreases cAMP levels, leading to reduced activity of the lac operon.
• C. It directly activates the lac repressor, turning off the lac operon.
• D. It enhances the binding of RNA polymerase to unrelated promoters.

Answer: (B)