Final answer:
The placement of perm rods that minimizes stress and tension on the hair is perpendicular to the base. Correct option is D.
Step-by-step explanation:
The placement of perm rods that minimizes the amount of stress and level of tension on the hair is perpendicular to the base (D).
When the perm rod is placed perpendicular to the base, it allows the hair to wrap around the rod evenly without any unnecessary pulling or bending. This minimizes the risk of breakage and damage to the hair.