A compound die will be used to blank and punch a large washer out of 6061ST aluminum alloy sheet stock 3.50 mm thick. The outside diameter of the washer is 50.0 mm and the inside diameter is 15.0 mm. Determine the punch and die sizes for the punching operation. TABLE 20.1 Clearance allowance value for three sheet metal groups. Metal Group A 0.045 0.060 1100S and 5052S aluminum alloys, all tempers 2024ST and 6061ST aluminum alloys; brass, all tempers; soft cold- rolled steel, soft stainless steel Cold-rolled steel, half hard; stainless steel, half-hard and full-hard 0.075 Select one: a. 20.42 mm b. 18.42 mm c. 15.42 mm d. 19.42 mm