Q.6 Choose the correct option regarding retrovirus.

(a) a RNA virus that can synthesis DNA during infection
(b) a DNA virus that can synthesis RNA during infection
(c) a ssDNA virus
(d) a dsRNA virus

(a) A retrovirus is a single-stranded RNA virus that stores its nucleic acid in the form of mRNA genome (5'cap and 3’poly A tail).

In most viruses, DNA is transcribed into RNA, and then RNA is translated into protein.
However, in retroviruses their RNA is reverse-transcribed into DNA, which is integrated into the host cell's genome (when it becomes a provirus) and then undergoes the usual transcription and transtational process to express the genes carried by the virus,

i.e., RNADNA RNA Polypeptide.