DNA is composed of four nucleosides: adenosine, cytidine, thymidine, and guanosine. If scientists introduced radioactive thymidine into the growth medium of the cells, it would be incorporated into the DNA molecule
A) at any point in the cell cycle.
B) during DNA replication.
C) as the cell enters G1 of interphase.
D) when centromeres split so the two chromosomes can be separated.