instruction: Given this paragraph about the description of wakesurfing, what is needed to generate the wave?
context: Wakesurfing is a water sport in which a rider trails behind a boat, riding the boat's wake without being directly pulled by the boat. After getting up on the wake, typically by use of a tow rope, the wakesurfers will drop the rope, and ride the steep face below the wave's peak in a fashion reminiscent of surfing. Wakesurfers generally use special boards, designed specifically for wakes.
response: a boat