Closure of stomata
Tyloses in vessels
Flaccidity of Bulliform cells
Shrinkage of air spaces in spongy mesophyll
Correct option is C. Flaccidity of Bulliform cells
Bulliform cells become flaccid due to water loss. This will make the leaves to curl inward to minimise water loss.So, the correct answer is 'Flaccidity of Bulliform cells'