The correct option is A Intake of carbon dioxide and the release of oxygen
Stomata is a pore, found on the underside of leaves, that facilitates gas exchange.
Carbon dioxide enters the plant through these openings by gaseous diffusion, which is used in photosynthesis . Oxygen produced as a by-product of photosynthesis diffuses out to the atmosphere through these same openings.
Also, water vapor diffuses through the stomata into the atmosphere in a process called transpiration.