The answer is D.) Some environmental change has happened that favors the red flowers. The reason is, this is the most logical answer, the other are close, but D.) makes the most sense.
D. Some environmental change has happened that favors the red flowers.
Explanation:
According to the given information, the original Phlox population had equal proportions of white, pink, and red flowers. During the study time, some changes in environmental conditions led to increase in survival and reproductive fitness of red flowers over the other two colors of the flower. Natural selection favored the red flowers which in turn led to their increase in the population.
