The correct option is A Sensory crista of the ampulla.
Within the ampulla of each semicircular canal is a complex mechanoreceptor structure, the crista ampullaris. The ampulla has sensory hair cells. When the perilymph in one of the semicircular canals moves, the hair cells in the crista ampullary are stimulated to send nerve impulses to the brain. This helps the brain to assess whether or not a person has their balance during body movements.