Stomata of a plant opens due to

Explanation

The correct answer is the influx of potassium ions into the guard cells of the stomata. When light is available, potassium ions are actively transported into these cells, leading to an increase in turgor pressure. This pressure causes the guard cells to swell and bend, resulting in the opening of the stomata for gas exchange. The other options are incorrect: the efflux of potassium ions would decrease turgor pressure and close the stomata, while the influx of hydrogen or calcium ions does not directly cause the stomatal opening mechanism.