Which describes a difference between an allosteric effector and a covalent modification?

A) Allosteric effectors activate enzymes, covalent modifications inactivate enzymes.
B) Allosteric effectors inactivate enzymes, covalent modifications activate enzymes.
C) Allosteric effectors utilize transient interactions, covalent modifications are more stable.
D) Allosteric effectors utilize more stable interactions, covalent interactions are more transient.
E) None, they're nearly the same.