A fish is swimming at a constant rate toward the ocean floor. The equation y = -7x - 3 can be used to represent this situation, where y is the depth of the fish in meters below sea level and x is the number of seconds the fish has been swimming.
Which statement best describes the depth of the fish, given this equation?

A. From a starting position of 7 meters below sea level, the fish is descending 3 meters per second.

B. From a starting position of 7 meters below sea level, the fish is ascending 3 meters per second.

C. From a starting position of 3 meters below sea level, the fish is descending 7 meters per second.

D. From a starting position of 3 meters below sea level, the fish is ascending 7 meters per second.