Answer:
Option (b).
Explanation:
DNA polymerase III is the enzyme used during the DNA replication in case of prokaryotes. This enzyme has high processitvity and acts as the main replicating enzyme. This enzyme has different subunit like alpha, beta, gamma and tau.
The beta subunit acts as the sliding clamp. The beta subunit is lies perpendicular to the DNA grooves as this orientation restrict the entry of the protein. This restriction helps in the sliding of the beta subunit of the DNA and continue the process of DNA replication.
Thus, the correct answer is option (b).