In swimming, which of the following kicks is used in the butterfly stroke?

The dolphin kick is the correct answer because it is the specific kicking technique used in the butterfly stroke. In this stroke, swimmers employ a simultaneous movement of both legs that undulates up and down, mimicking the motion of a dolphin tail. This kick allows for a smooth and powerful propulsion through the water, which is essential for maintaining speed and efficiency while performing the butterfly.

The other kicking techniques mentioned have distinct movements that are associated with different strokes. For instance, the scissor kick is primarily used in breaststroke, where the legs move in a manner similar to scissors opening and closing. The flutter kick is commonly employed in freestyle and backstroke, characterized by an alternating leg movement up and down. The whip kick, utilized in breaststroke, features a circular motion that helps propel the swimmer forward. Thus, the dolphin kick is uniquely suited to the rhythm and demands of the butterfly stroke.