The process of post ecdysial hardening and darkening of the cuticle is regulated by –

Correct option is D

After an insect molts (ecdysis), its new cuticle is soft. The hardening (sclerotization) and darkening (melanization) of this new cuticle is controlled by the hormone bursicon.
Bursicon is a neurohormone released after molting, which promotes tanning of the cuticle.
Moulting hormone (ecdysone) and juvenile hormone regulate earlier stages of molting and development.
Correct answer: (d) Bursicon hormone