This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
Formation of DNA using RNA template is done by 
Select and explain. 
A. DNA dependent RNA polymerase, B. Reverse transcriptase, C. DNA polymerase, D. RNA polymerase
B: Reverse transcriptase
Answer: B: Reverse transcriptase 
Explanation: There exists in one species of animal viruses (retroviruses) a class of enzymes capable of synthesizing a single-stranded and then a dsDNA molecule from a single-stranded RNA template. This polymerase termed RNA-dependent DNA polymerase, or "reverse transcriptase," first synthesizes a DNA-RNA hybrid molecule utilizing the RNA genome as a template. A specific virus-encoded nuclease, RNase H, degrades the hybridized template RNA strand, and the remaining DNA strand, in turn, serves as a template to form a dsDNA molecule containing the information originally present in the RNA genome of the animal virus.Ref: Harpers Illustrated Biochemistry, 30th edition, page no: 387