Final answer:
In mapping the positions of strategic groups in the industry's overall market space, using variables where big differences exist among the rivals is important.
Step-by-step explanation:
In mapping the positions of strategic groups in the industry's overall market space, the variable chosen as axes should be ones where big differences exist among the rivals. When the rivals differ on both variables, the locations of the rivals will be scattered, thus showing how they are positioned differently. Therefore, option d is correct.