B or c I’m not sure which one
I'm pretty sure it's igneous
Plants use carbon dioxide in a process known as photosynthesis. During photosynthesis, plants give off oxygen as a waste product. Carbon dioxide moves from the air into the leaves of plants through tiny openings in the plant's leaves. Oxygen moves out of the plant leaf through these same openings.
Therefore, a 10x eyepiece used with a 40X objective lens, will produce a magnification of 400X. The naked eye can now view the specimen at a magnification 400 times greater and so microscopic details are revealed. More on objective lenses here. Magnification is the ability to view an object as larger.