Which unit is used in the metric system to measure speed?

In the metric system, speed is defined as the distance traveled divided by the time taken to travel that distance. The correct unit for measuring speed is "meter per second" because it directly combines the units of distance (meters) and time (seconds) into a single measurement that reflects how fast something is moving.

When you express speed as "meters per second," you are indicating how many meters an object travels in one second, which provides a clear quantification of speed. This structure aligns with the principles of the metric system, where the base units can be systematically combined to express various physical quantities.

The other choices represent either distance measurements or units from different measurement systems. For example, kilometer and centimeter are both measures of length without incorporating time to express speed, and foot per second is a unit of speed in the imperial system, not the metric system. Therefore, "meter per second" is the appropriate metric unit for speed.