Frequency is measured in units of reciprocal time.
Period is measured in units of time.
Phase is a number without units that represents a fraction of a wave.
None of these is measured in meters, so none of them can be the answer.
It must be either amplitude or wavelength.
Amplitude is a quantity that's measured at one or two points in the same wave.
The question is talking about points on consecutive waves.
Wavelength is the only choice left. I know that`s correct.
