Which of the following units is the metric base unit of length?

• A. kilometer
• B. meter
• C. millimeter
• D. centimeter

Answer: (B)

Verified step by step guidance

1. Understand that the metric system is based on a set of base units for different physical quantities, such as length, mass, and time.
2. Recall that the base unit of length in the metric system is the unit from which other length units are derived by multiplying or dividing by powers of ten.
3. Identify the given options: kilometer, meter, millimeter, and centimeter. All except meter are multiples or submultiples of the meter.
4. Recognize that the meter is the fundamental unit of length in the metric system, and other units like kilometer (1000 meters), centimeter (0.01 meters), and millimeter (0.001 meters) are derived from it.
5. Conclude that the correct metric base unit of length is the meter.