21. Which statement is incorrect?
(A) The biosynthesis of dNTPs utilizes NTPs as source.
(B) Ribonucleotide reductase catalyzes ribose to deoxyribose in all biology.
(C) The biosynthesis of dTTP is first to convert dUDP to dUMP and subsequently to dTMP.
(D) The biosynthesis of dTDP from dTMP requires ATP as energy source.
(E) None of the above.