According to ADA Specification No. 28, what is the rate of increase in file diameter per running millimeter of length for a K-type file from point D0 to point D16?
Each number should represent diameter of instrument in 100th of millimeter at the tip. 
For example, a No. 25 K file shall have 0.25 mm at D1 and 0.57 mm (0.25 + 0.32) at D2. 
These sizes ensure a constant increase in taper, i.e. 0.02 mm/mm of the instrument regardless of the size.
0.02 mm per running millimeter of length
0.04 mm per running millimeter of length
0.06 mm per running millimeter of length
Parallel sided, so no increase in diameter