Mike May Studied the Relationship Between Cricket Behavior and the Ultrasonic

Mike May studied the relationship between cricket behavior and the ultrasonic cries of bats. Which statement constitutes a hypothesis?

A) He noticed that the hindwing farther from the source of the ultrasound didn't make a stroke as deep as the other hindwing of the insect.
B) He found that with every burst of ultrasound, the wings of the cricket seemed to stop.
C) He asked himself, was this symbiosis another mechanism that enabled the cricket to turn away from the ultrasound produced by a bat?
D) He proposed that if the wing farther from the ultrasound did not make a full stroke, it should produce less thrust-inducing a turn toward that side.