14. The fate of IMP is regulated by relative levels of ______ and ______; and energy to drive AMP synthesis is provided by ______ and energy for GMP synthesis by ______.
(A) IMP; PRPP; ATP; GTP
(B) PRPP; ATP; ATP; GTP
(C) AMP; ATP; GTP; ATP
(D) AMP; GMP; GTP; ATP
(E) none of the above.