Answer:
S phase.
Step-by-step explanation:
Cell cycle may be defined as the seroes of the steps that are important to increase the number by the division of the cell. Four main phases of cell cycle are G1 phase, S phase, G2 phase and M phase.
Cytarabine is a drug used for the treatment of acute myeloid leukemia and , chronic myelogenous leukemia. This drugs affect the cell cycle at the synthesis or S phase. The cytarabine causes the rapid conversion of cytosine into cytosine arabinoside triphosphate that plays an important role in the S phase of cell cycle.
Thus, the correct answer is S phase.