Answer: C) All of the preceding are true
Explanation: Velocity changes only when a force acts on an object and makes it accelerate. The only force acting on a ball when it's in motion after its thrown is gravity (if air resistance is neglected). Gravity acts on the y axis, so there is only an acceleration downward in the -y direction, thus only the y-component of its velocity will change. This makes all of the individual statements a b and d true.