What are the cells that make the leaves curl in plants during water stress?

Which of the following is absent in a monocot leaf?

Assertion: Bulliform cells are useful in the unrolling of leaf.
Reason: Bulliform cells store water.

In the leaf of a plant,the vascular bundles are located in the $..............$

$I.$ Sunflower seed
$II.$ $A$ wheat leaf
$III.$ Pea plant
$IV.$ Leaf blade of grass
Bulliform cells are present in which of the above plants?

The epidermis in a dorsiventral leaf:
$(a)$ Covers both adaxial and abaxial surfaces
$(b)$ Is not covered by cuticle
$(c)$ Bears more stomata on the upper side
$(d)$ May even lack stomata on the upper side
Which of the above statements are correct?