What relationship exists between the densities of predator and prey populations, according to the graph "Population Change of a Predator and its Prey Over Time"?

Image shows a graph depicting the population change of a predator and its prey over time. The prey population is indicated by a black line that rises and falls over time. The predator is indicated by a gray line that rises after the black line rises, and falls after the black line falls.


When the prey population peaks, the predator population is decreasing.
As the prey population decreases, the predator population remains constant.
After the prey population increases, then the predator population also begins to increase.
As the prey population increases, the predator population remains constant.