The most common would be kilometers.
Some might use centimeters if they're feeling risky.
Others might even go down to nanometers, or .000000000001 kilometers. This would give them a very accurate answer.
Worldwide use:
The kilometre is used worldwide as a unit used for expressing distances between geographical locations on land, and in most countries is the official unit for this purpose.
Kilometers
time taking to walk
Type your answer here...kilometers
A microgram.
kilometre
Meters
distance
A global positioning system (GPS)
meters
I would assume that you would use cm or even mm if you wanted to be more accurate
A metric ruler.
Kilometers
kilometers
meters
Metres (in a built-up area), kilometres if across open spaces.
Miles is best.
A calculator would be between 100 and 150 millimetres.