The correct answer is option 2: Guard cells. Guard cells are the specialized epidermal cells that surround the stomatal pore. They play a crucial role in controlling the opening and closing of the stomata. When the guard cells are turgid or swollen with water, they become curved and cause the stomatal pore to open, allowing for gas exchange and transpiration. On the other hand, when the guard cells lose water and become flaccid, they become straight and close the stomatal pore to prevent excessive water loss through transpiration. Guard cells also have chloroplasts, which enable them to perform photosynthesis and provide energy for the opening and closing of stomata. Therefore, out of the given options, the correct term for the specialized epidermal cells surrounding the stomatal pore is guard cells.