The correct option is B Fujino
The mechanism with which water moves into the guard cells has been explained to be due to active potassium ion transport mechanism. Fujino (1967) observed through his experiments that stomata opens when there is an influx of potassium ions into the guard cells. ATP helps in the entry of K+ ions into the guard cells. The increase in the concentration of potassium ions increases the osmotic concentration of the guard cells thereby leading to the opening of the stomata.