ATP is a cosubstrate of the enzyme PFK-1. In most species ATP is also an inhibitor of PFK-1 at higher concentrations. This seems to violate Le Chatelier's Principle. Which statement below would provide a suitable explanation?

A) PFK-1 must be phosphorylated by ATP in the active site and the phosphorylated PFK-1 must be the less active form. B) There must be another cofactor interacting with ATP at high concentrations to achieve inhibition of PFK-1.C) ATP actually activates the reverse of the reaction preceding the PFK-1 step in the pathway. It likely has no direct effect on PFK-1.D) There are two sites on PFK-1 that bind ATP. One is the active site; the other is the regulatory site where inhibition occurs.