Earth's gravity attempts to change the velocity of all objects on earth's surface toward at a rate of 9.8 meters per seconds squared.

The answer is to the ground.

Gravity refers to the force that holds together the universe. On Earth, the gravity attempts to change the velocity of all the objects on the Earth's surface toward the ground at a rate of 9.8 meters per second squared according to Galileo. 

The correct answer is a. we know this because n (hap) + n (hap) = 2n (dip).