Statement A: Grass leaves show hygroscopic movements.
Statement B: Epidermis of grass leaves have bulliform cells.

Grass leaves show inrolling of their lamina towards midrib during dry spell due to loss of water from the motor cells. When water is available the bulliform cells gain water and become turgid which results in unrolling of lamina and the lamina is spread out. Rolling of lamina hides some stomata and thereby decrease the water loss by transpiration.