A biologist is conducting an experiment to determine how light affects the reproduction of Bacteria X. The biologist is trying to decide the best way to conduct his experiment in order to collect meaningful data.

Which of the following experiments would help him collect the best data?
A.
Place a Petri dish with Bacteria X in a moist, dark area and record the rate of reproduction over time.
B.
Place a Petri dish with Bacteria X in a lighted area and a Petri dish with Bacteria Y in a darkened area, and then observe the rate of reproduction over time.
C.
Place a Petri dish with Bacteria X in a sunny window and an identical Petri dish under a grow lamp.
D.
Place a Petri dish with Bacteria X in a lighted area and a Petri dish with the Bacteria X in a darkened area, and then observe the rate of reproduction over time.