A. Sugar... Because the others are mixes of things and combinations. Sugar is pure and on its own.
I hope this helps!
Mentos reacts to coca-cola because of the sugars and then they expand which causes the soda to explode out of the open container. this is a chemical reaction because it cause the sugars to expand which you can't see happen.
The answer is A cause the water breaks down the rocks into small pieces which are called sediments. These things later on turn into rocks with pressure and heat
