Which is most likely the length of a students textbook

approximately 30 cm

Explanation:

Length is defined as extent of something from end to end. It is a measure of distance and the unit of length is meter(m) that is a base unit.

Measurement is defined as a collection of numerical data that is to describe a property of an object. It is by comparing the quantity with the standard unit. According to International system of units there are seven base units for all types of physical measurements , the kg for mass, the meter for distance, the candela for luminous intensity, the ampere for current, the kelvin for temperature, the second for time and the mole for amount of a substance.

your answer should be c) enjoy!