Speedometer of a car measures
The correct option is (B) instantaneous speed
A speedometer is a device that measures the speed of the vehicle, at any instant of time i.e measure instantaneous speed.
Hence, option (B) is correct.
The explanation for wrong answers
The average speed is given as
Averagespeed=TotaldistancetraveledTotaltimetaken
Average velocity is given as
Averagevelocity=TotaldisplacementTotaltimetaken