A "trend routing technology" logo appears on screen. "knife sharpening using a diamond bench stone" appears. two men <sep> (A) are inside a gyre sitting on a bench sharpening knives while women wait outside in the stands ready and ready. (B) finely sharpen knives using a long sharpening knife. (C) discuss, and one appears with a white " chinese slanting " stone. (D) demonstrate sharpening a knife using a honing stone.
D