When anchoring AM–2 matting, make the anchor ditch a. 24 to 48 inches deep and cut it at a 30°to 45°angle. b. 48 to 60 inches deep and cut it at a 45°to 60 °angle. c. 18 to 24 inches deep and cut it at a 45°to 60°angle. d. 18 to 24 inches deep and cut it at a 15°to 30°angle