A LiDAR sensor on a marine research vessel measures the profile of ocean waves relative to a flat seabed reference datum, as shown in the diagram.
What is the amplitude of the waves?
4.7 m4.7\text{ m}4.7 m
6.4 m6.4\text{ m}6.4 m
8.1 m8.1\text{ m}8.1 m
9.4 m9.4\text{ m}9.4 m