Consider a Culture of 10,000 Cells That Double to 20,000

Consider a culture of 10,000 cells that double to 20,000 cells. If measuring 100 mutations in the population, the mutation frequency would be

A) 100 mutations / ~4,500 genes = 0.022.
B) 100 mutations / 1 generation = 100.
C) 100 mutations / 20,000 cells = 0.05.
D) 100 mutations / 10,000 new cells = 0.001.
E) (100 / ~4,500 genes) / 10,000 new cells = 0.0000022.