Can someone answer the 2 questions on the screenshot?

For general projectile motion, when the projectile is at the highest point of its trajectory, its acceleration is zero? a)the horizontal and vertical components of its velocity are zero. b) its velocity is perpendicular to the acceleration. c)the horizontal component of its velocity is zero. d)its velocity and acceleration are both zero.

Why is the energy that results from a roller coaster's position at the top of a hill referred to as potential energy?

Amother used 150 watts of power to raise a 15 newton object in a time interval of 8.0 seconds. through what vertical distance was the object raised ?