Context: Read the text about an animal in motion.
A horse was grazing at the top of a small hill. The horse got thirsty and ran toward a river at the bottom of the hill.
Complete the statement. Assume that the horse's mass did not change.
The gravitational potential energy stored between the horse and Earth () as the horse ran toward the river.
A. increased
B. decreased
C. stayed the same
Answer with the option's letter from the given choices directly.

B