Option (b) is correct. The phosphorylated
nucleotides are deATP (deoxy Adenosine
Triphosphate), deCTP (deoxy Cytidine Triphosphate),
deTTP (deoxy Thymidine Triphosphate). These
triphosphates serve dual purpose. These act as substrate
as well as provide energy for polymerisation of
nucleotides by releasing energy after dissociating the
phosphate group.