The correct option is C S phase, cytoplasm
Centrioles are organelles that lie near the nucleus in the cytoplasm of animal cells. They help in cell division by organizing spindle fibres. Centrioles duplicate during the S phase of the cell cycle and it results in the formation of four centrioles prior to cell division. They help in distributing the duplicated genetic material equally. Also, during S phase, DNA replication occurs inside the nucleus. During the G2 phase, there is overall cell growth and proteins needed for cell division like tubulin are synthesized.