Final answer:
The enzymes involved in proofreading, mismatch repair, and nucleotide excision repair include DNA polymerase and DNA ligase; endonuclease is also involved in nucleotide excision repair but not proofreading itself. Therefore, the correct answer to the student's query is (D) DNA Polymerase and DNA Ligase Only.
Step-by-step explanation:
The enzymes required in proofreading, mismatch repair, and nucleotide excision repair are several and perform different functions. Proofreading is primarily accomplished by DNA polymerase during replication. It checks for accuracy as it synthesizes new DNA strands and excises incorrect bases right away. In mismatch repair, which happens after replication, mispaired nucleotides are recognized and excised. This involves a cooperation between endonuclease that cuts out the incorrect base and surrounding DNA, DNA polymerase that fills in the correct nucleotides, and DNA ligase that seals the nick in the DNA backbone by forming a phosphodiester bond.
Nucleotide excision repair is particularly important for repairing bulky lesions such as thymine dimers. Here, an endonuclease cuts out a section of the strand that includes the damage, DNA polymerase fills in the gap using the undamaged strand as a template, and DNA ligase completes the repair by sealing the strands together.
So, the correct answer to the question is (D) II and III Only, meaning DNA Polymerase and DNA Ligase.