The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
Some species of amphibians and reptiles can rapidly change colour through mechanisms that translocate pigment and reorient reflective plates. This process, often used as a type of camouflage, is called physiological colour change or metachrosis. Colour changing signals can be hormones or neurotransmitters and may be initiated by changes in mood, temperature, stress or visible changes in the local environment.