Walt is gathering data about how fa students travel to school each day. What is the best unit of measure to use when gathering his data?

It would either be 'miles' or 'kilometers' depending on which system of measurements you use.

Assuming the word was supposed to be 'far',

the best unit of measure is a measure of legnth or distance, the bigger the better so use miles or kilometers, depending on where you live because english=miles and kilometers=metric

the best unit is kilometers (or miles depending of choice)