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.
-In the Luria Delbruck experiment, what did the appearance of a bacterial colony on a petri plate indicate?

A) The bacterial colony was derived from one initial cell that was resistant to infection by the bacteriophage.
B) The bacterial colony was made up of many cells that became resistant to bacteriophage infection independently.
C) A colony formed when a bacterial cell was not resistant to bacteriophage infection.
D) The bacterial cells that made up a colony were resistant to antibiotic.