Final answer:
The wave speed is the distance traveled divided by the time taken, which in this case is 6 meters divided by 1 second, resulting in a wave speed of 6 m/s.
Step-by-step explanation:
The wave speed of a wave traveling an average distance of 6 meters in one second is calculated by simply dividing the distance traveled by the time it took. In this case, wave speed = distance / time = 6 meters / 1 second, which equals 6 m/s. Therefore, the correct answer is D. 6 m/s.