The correct answer is B. Stomata.
Stomata are tiny pores found on the underside of leaves. They allow for the exchange of gases, such as carbon dioxide and oxygen, between the plant and the atmosphere. Stomata are also responsible for the transpiration of water vapor from the plant.
Chloroplasts are organelles found in plant cells that contain chlorophyll. Chlorophyll is a green pigment that absorbs sunlight and uses it to convert carbon dioxide and water into glucose and oxygen during photosynthesis.
Chlorophyll is not a pore, and it does not allow for the exchange of gases.
Vacuoles are large, fluid-filled sacs found in plant cells. They store water, nutrients, and waste products. Vacuoles are not pores, and they do not allow for the exchange of gases.