The International System of Units (SI) establishes fundamental units for various physical quantities. For distance, the SI unit is the meter (m), and for time, it is the second (s). Since speed is defined as distance traveled per unit time, its standard SI unit is derived by combining these fundamental units, resulting in meters per second (m/s). Other options like km/h, m/min, and cm/s are valid units of speed but are not the designated SI unit.