Cause of sleepiness in carnation is

Answer: Option C

The cause of sleepiness in carnation is Ethylene.
The term "sleepiness" as applied to flowers is usually confined to carnations. It is characterized by partial closing of the flower due to an incurving or curling of the petals.
They have ethylene-sensitive floral organs and show characteristic senescence patterns, including petal in rolling, which coincides with the climacteric increase in ethylene biosynthesis.