Refer to the figure.
The top figure's findings best support the proximate-level hypothesis that

A) crickets use the light and dark as environmental cues to entrain their circadian rhythm.
B) crickets have an internal clock that maintains a regular cycle of calling in the absence of environmental cues.
C) it is adaptive for male crickets to have a circadian rhythm in order to match female activity and increase chances of reproduction.
D) the molecule juvenile hormone (JH) is responsible for regulating the cricket's circadian rhythm.