Receptors that sense the change in atmospheric pressure are classified under mechanoreceptors. Three pressure receptors are namely Pacinian corpuscles, Ruffini endings and Krause end bulbs which are located in skin. This makes option A incorrect. The three semicircular canals lie at right angle to each other in vestibular apparatus of inner ear and are filled with endolymph; this arrangement senses the change in movement (acceleration or deceleration) or position. The mechanism includes movement of cupula in response to movement of endolymph within the canal causing the bending of cilia to generate the nerve impulse. This makes option C correct and option D incorrect. Migratory birds and animals have receptors in their brain which are activated by direction of sunlight and orient their body at certain angle in relation to sun. This makes option B incorrect. Correct answer is C.