Refer to the Figure

Refer to the figure.
The birth and death rates of a population of garter snakes were monitored over 11 years, during which time population density varied considerably. According to the figure, which statement about the populations is true?

A) Density-independent factors are regulating population size.
B) At high population sizes, the death rate is higher than it is at low population sizes.
C) Birth rate declines at high population sizes.
D) Birth rates equal death rates.