The bean shaped cells which enclose stomatal pore are calledGuard cellsSubsidiary cellsStomatal apertureCuticle

The correct answer is Guard cells.

Guard cells are specialized cells that surround the stomatal pores in the epidermis of leaves. Their function is to regulate the opening and closing of these pores, which are essential for gas exchange (like oxygen and carbon dioxide) and transpiration in plants. When the guard cells swell with water, they become turgid and bend away from each other, opening the stomata. Conversely, when they lose water, they become flaccid, causing the stomata to close. This process is crucial for maintaining homeostasis in plant physiology, particularly during varying environmental conditions.