Answer:
A- Relieving strain in the DNA ahead of replication fork.
Explanation:
During transcription or replication, DNA double helixed strand unwinds catalysed by the helicase enzyme, they break the hydrogen bonds that holds the two strands together. When DNA unwinds, supercoils are created in the replication fork, if it is not dealt with, transcription or replication will come to a halt. Topoisomerase enzymes are there to relieve DNA by cutting the phosphate backbone of either single or both strands of DNA, preventing supercoils.
I’m not really sure but i think it’s true
