Answer:
B. during the S phase of the cell cycle
Explanation:
DNA replication occurs during the S phase of cell cycle in which the genetic content of a cell double folds so that when the cell divides into two equal halves one set of the genetic content could be passed on to the daughter cell. S phase is also known as synthesis phase. S phase is the phase of cell cycle which is in between G1 phase and G2 phase and the duration of S phase is around eight hours.