It would be normal to use either meters or feet, but you can use any unit for length (inches, cm, mm, km, etc.)
A metre.
feet
miles or kilomiters
miles
A metres, for an approximate measure, a centimetre for a more accurate measure.
A metre.
Feet, Metres or some on the number of wheels the truck has eg. 12 wheeler
Feet would be nice, or meters where the metric system reigns.
By unit of length and distance and conversion ,we can say that the most appropriate unit to measure the length of a finger is cm.
Inches
cm
Tonnes
tons
I would use feet
You would use meters.
centimeter
yards