Which horse gait is characterized by four beats?

The gait characterized by four beats is indeed the walk. In a walk, each hoof hits the ground independently, producing a distinct rhythm that can be noted as each hoof raises and falls in succession: left hind, left front, right hind, and right front. This four-beat movement allows for a steady, smooth flow that is easy for both horse and rider to maintain.

The other gaits listed are defined by different footfall patterns. The trot has a two-beat rhythm where diagonal pairs of legs move together, creating a bouncing motion. The canter has a three-beat pattern with one hoof hitting the ground alone followed by a pair of hooves and then a pause, while the lope, which is a type of canter, follows the same three-beat rhythm. Hence, it is the walk that stands out with its unique four-beat structure.