Answer:
a. located on the inner surface and oriented perpendicular to the minor and major grooves of DNA.
Step-by-step explanation:
The beta subunit of the Polymerase III is a ring-shaped clamp that embraces DNA in a central 35-angstrom (A) hole and plays an important role in the processivity of the enzyme during DNA replication. The beta subunit of the Polymerase III is a homodimer composed of two monomers (each of 366 amino acids), where each monomer provides one half of the ring-shaped clamp. In the beta dimer, this hole is sufficiently large to accommodate the double helix of DNA.