Guard cells in monocot leaves are

Answer: Option D

Guard cells in monocot leaves are Dumb-bell shaped.
Monocots contain dumbbell-shaped guard cells, surrounding their stomata. Monocots contain stomata in both upper and the lower epidermis of leaves.
Guard cells optimize leaf gas exchange in response to changing environmental conditions and their turgor is controlled by alterations in atmospheric CO₂ concentration, light intensity, humidity and the drought hormone abscisic acid.