Answer:
black
Explanation:
In white light, a red apple absorbs all the colors (including green) of the spectrum except red, which it reflects.
A green filter absorbs all the colors of the spectrum except green, which is transmitted through the filter (and comes through as green light).
When the green light shines on a red apple, the red apple absorbs the green light.
Since there is no red light shining on the apple, there is no red light to reflect, so the apple appears black.
Hope this helps!
