Who discovered "Reverse transcription"?

$A$ discrete multiprotein structure on the chromosome which contains enzymes for $DNA$ duplication is called as

During $DNA$ replication,Okazaki fragments on the lagging template are always formed in $A$ direction $B$.

Replication was allowed to take place in the presence of radioactive deoxynucleotide precursors in $E. coli$ that was a mutant for $DNA$ ligase. Newly synthesised radioactive $DNA$ was purified and strands were separated by denaturation. These were centrifuged using density gradient centrifugation. Which of the following would be a correct result?

$DNA$ gyrase,the enzyme that participates in the process of $DNA$ replication,is a type of:

At what time intervals did Meselson and Stahl take samples after transferring the bacteria to a $^{14}NH_{4}Cl$ medium?