If a Block Is Set Sliding on a Huge Frictionless

Multiple Choice

If a block is set sliding on a huge frictionless plane in contact with the Earth,it will NOT continue to move at constant speed because

A) of its inertia.
B) gravity will pull in a non-perpendicular direction as the block gets farther out on the plane.
C) gravity gets weaker as distance increases.
D) it is not free from the shackles of Earth's gravity.