The basic unit of speed is represented by the option 'D', which is meters per second (m/s). Speed is a measure of how fast an object is moving, and it is calculated by dividing the distance traveled by the time taken.

Explanation:

Speed is a scalar quantity, which means it only has magnitude and no direction. It is different from velocity, which is a vector quantity that includes both magnitude (speed) and direction.

The basic unit of distance is the meter (m), and the basic unit of time is the second (s). Therefore, when we divide the distance traveled (in meters) by the time taken (in seconds), we get the speed in meters per second (m/s).

Let's understand this concept with an example:

Suppose a car travels a distance of 100 meters in 10 seconds. To calculate the speed, we divide the distance by the time:

Speed = Distance/Time
= 100 meters / 10 seconds
= 10 meters per second (m/s)

Therefore, the speed of the car is 10 m/s.

Other options:

a) km/min: Kilometers per minute is not the basic unit of speed because the basic unit of distance is the meter, not kilometer, and the basic unit of time is the second, not minute.

b) m/min: Meters per minute is also not the basic unit of speed because the basic unit of time is the second, not minute.

c) km/h: Kilometers per hour is a commonly used unit of speed, especially in road transportation. However, it is not the basic unit of speed. It is derived by converting the basic unit of speed (m/s) to kilometers per hour.

To convert m/s to km/h, we multiply the speed in m/s by 3.6:

Speed (km/h) = Speed (m/s) x 3.6

Conclusion:

The basic unit of speed is meters per second (m/s). It is obtained by dividing the distance traveled (in meters) by the time taken (in seconds).