Which sentence uses commas correctly?
(a)when a bat’s squeaks hit an object, they echo back to the bat’s ears, and that is how bats use sound to find their prey in the dark.
(b)when a bat’s squeaks hit an object, they echo back to the bat’s ears and that is how bats use sound to find their prey in the dark.
(c)when a bat’s squeaks hit an object they echo back to the bat’s ears, and that is how bats use sound to find their prey in the dark.