Luria and Delbruck Grew Many Liquid Cultures of Bacteria Then

Luria and Delbruck grew many liquid cultures of bacteria then spread a small sample of each culture on nutrient agar infused with bacteriophage in separate petri plates. They assayed the number of bacterial colonies that formed on each plate.
-When Luria and Delbruck assayed bacterial growth on the petri plates, what did they find?

A) All plates had some bacterial colonies; some plates had more bacterial colonies than others.
B) Some plates had no bacterial colonies; others had varied numbers of colonies.
C) All plates had a similar number of bacterial colonies.
D) Some plates had no bacterial colonies; all of the other plates had a similar number of bacterial colonies.
E) No bacterial colonies formed on any of the plates.