Correct length of jacket sleeves

Dear All:

I yesterday bought a black label Armani suit (I know Armani is not terribly popular on this forum!) and need to make sure that I get the correct length of the jacket sleeves: when I stand with my hands falling down straight should the sleeve fall just below my wrist, just above my wrist or exactly at the wrist? I read somewhere on this forum that the sleeves should show about 1/4 inch of the shirt sleeve: is this true and if it is does it mean that the jacket sleeve should fall just above the wrist?
Regards.