The correct answer is:
The force of his hand pushes up on the apple with equal magnitude to the force of gravity, which pulls down on the apple. The two forces are balanced, so the apple doesn't fall.
In this situation, the force exerted by the boy's hand on the apple (the upward force) is equal to the force of gravity acting on the apple (the downward force). Because these forces are equal and opposite, they are balanced, resulting in no net force on the apple, and therefore it does not fall.