Volume = 873 - 50 = 723 cm^3
I think the correct answer would be one half the wavelength. Waves would "feel bottom" when the water is at the depth of 0.5 of the wavelength. "Feel bottom" is a term used to describe that the depth of water affects the wave properties. Hope this answers the question.
The answer Is B! Good luck
1. A basketball was thrown in the air and falls to the ground