During DNA replication, what is the primary role of DNA gyrase (a bacterial type II topoisomerase) ahead of the replication fork?

• A. It synthesizes short RNA primers required for DNA polymerase to begin DNA synthesis.
• B. It relieves positive supercoiling (torsional strain) by introducing negative supercoils via transient double-strand breaks and resealing DNA.
• C. It unwinds the parental DNA duplex by breaking hydrogen bonds between base pairs at the replication fork.
• D. It joins Okazaki fragments on the lagging strand by sealing nicks in the sugar-phosphate backbone.

Answer: (B)