This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Replication, Subject name: Biochemistry
Which of the following is the cofactor for Prokaryotic DNA ligase? 
Select and explain. 
A. Tetrahydrobiopterin, B. ATP, C. NAD, D. FAD
C: NAD
Answer: C: NAD 
Explanation: DNA ligase : Enzyme that catalyse the formation of phosphodiester bond. During replication, the nick is sealed by DNA ligases. Use : In recombinant DNA technology as molecular glues. Cofactors : In Prokaryotes - NAD In Eukaryotes - ATP