URGENT MATH HELP!

Which shows the conversion of 0.21 millimeters to inches?

There is 0.03937 inch in 1 millimeter.

A.
0.21 mm × 0.03937 in./mm = 0.0083 inches

B.
0.21 mm + 0.03937 in./mm = 0.24937 inches

C.
0.21 mm ÷ 0.03937 in./mm = 5.34 inches

D.
0.21 mm × 0.03937 in./mm = 8.3 × 10^-2 inches