Wavelength is

a. the time in which an oscillation repeats itself.

b. the distance in which an oscillation repeats itself.

c. the distance from one end of an oscillation to the other.

d. the maximum displacement of an oscillator.

e. not discussed in this chapter.

b. the distance in which an oscillation repeats itself.

Explanation:

When a wave travels on the surface of water, the medium particle oscillates up and down remaining at the same place. They push their oscillation forward in the direction in which wave moves. wave length is distance between two consecutive oscillating particles having same phase of oscillation. When an oscillation repeats itself, they come to the same phase as the phase in the beginning.

Hence second option is correct.