What effect would a loss-of-function mutation have on the expression of the gene encoding the catabolite activator protein of the lac operon?

• A. Low expression in the presence of lactose and off in its absence, regardless of the presence or absence of glucose
• B. High expression in the presence of lactose and off in its absence, regardless of the presence or absence of glucose
• C. Low expression in the presence of glucose and off in its absence, regardless of the presence or absence of lactose
• D. High expression in the presence of glucose and off in its absence, regardless of the presence or absence of lactose