Answer:
D. vertically.
Step-by-step explanation:
When sharpening a knife with a steel rod, it is important to hold the rod vertically with the tip firmly pressed against the counter. The knife should then be held at a 20-degree angle against the steel rod and moved down and across the rod in a sweeping motion. This process helps to straighten and align the edge of the knife, resulting in a sharper blade. Holding the rod horizontally, diagonally, or rotating it between horizontal and vertical positions would not provide the correct angle for sharpening the knife.