Final answer:
The correct answer is d) Ligase-4, which is DNA ligase IV, involved in V(D)J recombination to join coding and signal ends as well as repair double-strand breaks in DNA.
Step-by-step explanation:
The name of the DNA ligase used to join both the coding and signal ends during V(D)J recombination is DNA ligase IV (Option d). This enzyme works in conjunction with other proteins, such as XRCC4, to repair double-strand breaks by connecting the 3'-OH end of one DNA fragment to the 5' phosphate end of another DNA fragment, which is essential for the joining phase of V(D)J recombination in immune cells.
DNA ligase I is typically involved in the replication process, where it seals the nicks between Okazaki fragments on the lagging strand. The DNA ligase enzyme is crucial for maintaining the integrity of the DNA structure and for genetic processes such as DNA replication and repair.