Final answer:
Ligase makes a nick in the double-stranded DNA to separate the strands during DNA replication.
Step-by-step explanation:
The correct answer is c) Ligase.
During the DNA replication process, Ligase makes a nick in the double-stranded DNA so that each strand separates. Ligase is responsible for joining the Okazaki fragments on the lagging strand together into one continuous DNA strand.
Helicase separates the DNA strands at the origin of replication, Primase synthesizes RNA primer which is used by DNA polymerase to form a daughter strand, and DNA polymerase synthesizes the leading strand and Okazaki fragments.