Cell A has two times the DNA content as Cell B. Both cells belong to the same organism. Which of the following is the best explanation for why this is true?
A. Cell A is in S phase; Cell B is in G1 phase
B. Cell A is in S phase; Cell B is in G2 phase
C. Cell A is in G1 phase; Cell B is in S phase
D. Cell A is in G2 phase; Cell B is in G1 phase