Answer:
A. A disease in the population of rabbits.
Explanation:
I would say it is as a result of disease in the population of rabbits.
From the graph we would see that the grass population gradually increased this is as a result of the number of rabbits feeding on it decreased.
The four populations started out at their ideal values, it is likely that these changes were the result of a disease.
Because the rabbit population was the first to decrease, it is most likely that the disease occurred in the rabbit population, once this happen the snake population then decreased because its food supply (the rabbits) decreased. Since the snake population decreased, the hawk feeding on the snake population also decreased.
So the answer is A
A disease in the population of rabbits.