Hello,
Here is your answer:
The proper answer to your question is option D "gravity". Gravity is what pulls a object to the ground once its dropped for example if you drop a bowling ball it will hit the ground fast and hard because of its weight (mass) but if you drop the bowling ball in space where there's less gravity it will hit the moon less faster then it will hit the ground on Earth because of how there's not a lot of gravity!
Your answer is D.
If you need anymore help feel free to ask me!
Hope this helps!
