choose most reasonabl unit of measure .write mm,cm,dm,m,km

Question

thickness of a window

When you consider that a meter = about 39.6 inches, what would be the most reasonable unit to measure the thickness of window?

mm = 1/1000 m
cm = 1/100 m
dm = 1/10 m
km = 1000 m

You choose.

I hope this helps. Thanks for asking.