Janet and Megan are debating the use of student discounts by local stores near school. Janet argues, "When stores offer discounts to students with valid identification, it is price discrimination, because they are attempting to separate the market into two groups—each with different demands for that particular good." Megan responds with, "This is not a form of price discrimination, because there is no age restriction for students. Economists generally agree with :

a. Dina
b. Antonio