For instance, the designation 6 WS 13 denotes a window opening with single shutter having width equal to 6 modulus i.e. _____ and height equal to 13 modulus i.e. ____?

• A. 600 mm, 13 mm
• B. 6 mm, 13000 mm
• C. 600 mm, 1300 mm
• D. 6 mm, 13 mm