Answer:
Product Class
Explanation:
The product class positioning strategy consists in the comparison between two classes of products that are substitutes of each other, with the goal of highlighting the advantages of one over the other.
Mass transit is a substitute for private transit because they both have the same basic goal: allowing a person to move from one place to the other.
Those who are pro-mass transit then, try to highlight what makes mass transit different, or better, from individual transit. (more comfort, less traffic, less parking headaches, etc).