The correct optionis: (d) epidermis.
Explanation:
Bulliform cells are present in epidermis. These epidermal cells are found in the upper leaf epidemis of poaceae and other monocotyledons. Turgor changes in bulliform cells are responsible for the inrolling and unrolling of leaves. e.g maize, psamma grasses. Therefore, they are also called motor cells. They are highly vacuolate and can store water.
