Which of the following is the SI unit used to measure length?

• A. centimeter
• B. inch
• C. meter
• D. foot

Answer: (C)

Verified step by step guidance

1. Understand that the International System of Units (SI) is the modern form of the metric system and is the standard for scientific measurements worldwide.
2. Recall that the SI base unit for length is the 'meter', which is defined based on the distance light travels in a vacuum in a specific fraction of a second.
3. Recognize that units like centimeter, inch, and foot are not SI base units; centimeters are derived metric units, while inches and feet are part of the imperial system.
4. Identify that among the options given, 'meter' is the correct SI unit for measuring length.
5. Conclude that the meter is the fundamental unit for length in the SI system, and all other length units can be converted to or from meters.