Which enzyme present in retroviruses converts single stranded RNA into a double stranded viral DNA?

Q. Which of the following is correct regarding HIV?

I.HIV is a retrovirus with double stranded RNA.
II.HIV is a retrovirus that contains single stranded RNA.
III.HIV is a non-enveloped retrovirus with double stranded stranded RNA molecules.
IV.HIV causes severe immunodeficiency in the due course of its infection.

Q. The viral enzyme _________ causes the host cell to synthesize a double strand of DNA complementary to the viral RNA.

Q. Match List I(Enzyme) with List II(Function) and select the correct answer using the codes given the lists.

List-I	List-II
a. DNA Ligase	$1$. Catalyses the covalent union of segments of an interrupted sugarphosphate strand in double-stranded DNA
b. DNA polymerase	$2$. End nuclease that digests either single stranded or double stranded DNA
c. DNase I	$3$. Produces single or double stranded breaks in DNA during replication to release tension brought about by the separation of double strands
d. DNA topoisomerase	$4$. Catalyses the formation of DNA worn deoxyribonucleotides using one strand of DNA as template

Q. Melting temperature for double stranded molecules are converted into single stranded molecules. Which one of the following DNA will have the highest melting temperature?