A Population of T Cells Was Stimulated to Proliferate in Response

Multiple Choice

A population of T cells was stimulated to proliferate in response to a particular antigen.A sample of 1000 stimulated cells was analyzed by fluorescence-activated cell sorting (FACS) for total DNA content.Of the 1000 cells,400 had a 2n amount of DNA,200 had a 4n amount of DNA,and the remaining 400 cells had between a 2n and 4n amount of DNA.Additional immunofluorescence analysis revealed that 200 of the cells were in various stages of M phase and that M phase lasted 2 hours.What is the total length of the cell cycle?

A) 8 hours
B) 12 hours
C) 18 hours
D) 20 hours
E) 24 hours