Which unit is the standard measurement of length in the metric system?

The meter is the fundamental unit of length in the metric system, which is the decimal-based system of measurement widely used around the world. It serves as the base unit from which other measurements of length are derived and is integral to various scientific and engineering applications. The definition of the meter is based on the distance light travels in a vacuum in a specific fraction of a second, which provides a precise and universally accepted standard.

While the other options represent measurements related to the metric system, they focus on different quantities. The CGS (centimeter-gram-second) is a system of units that include centimeter for length but is not the standard metric unit itself. The liter is a unit of volume, and the gram is a unit of mass. Understanding that the meter is the standard unit of length helps to navigate and apply the metric system effectively in various contexts, including scientific calculations, engineering designs, and everyday measurements.