Answer: Option A, speed
Step-by-step explanation:
The rate at wich distance is covered is also the rate at wich the position changes, for example, if you cover 4 meters in 1 second, this rate is 4m/s, this is speed.
Velocity is when speed has also a direction, for example, 4m/s to south, this is a vector.
acceleration is the rate of change of the velocity.
Displacement is the change in position over a period of time.