Final answer:
At the highest point of its trajectory, the golf ball's vertical velocity component is zero, and if we're assuming the ball travels straight up without a horizontal component, the kinetic energy of the golf ball is also zero because kinetic energy is dependent on speed, which is zero at the peak of an upward launch.
Step-by-step explanation:
The question involves finding the kinetic energy of a golf ball at its highest point in its trajectory, given it was projected with an initial speed. When a projectile reaches its highest point, its vertical component of velocity becomes zero, and if we neglect air resistance, the only movement it has is the horizontal component of the initial speed. However, since we're not given any horizontal speed and typically for such a problem the initial speed refers to the magnitude of the vector which includes any horizontal component, we can assume for this scenario that the ball goes straight up and thus the kinetic energy due to horizontal movement would not be considered, making it zero (Answer a).