A News Magazine Offers Students a Discount on the Regular

A news magazine offers students a discount on the regular subscription rate.The total number of subscriptions is optimal,and,at the current prices,the marginal revenue from the last subscription sold to a student is $6,while the marginal revenue from the last subscription sold to a regular customer is $10.In order to maximize profit,the magazine should

A) stop offering students a discount on the regular subscription rate.
B) offer students a higher discount (lower the price to students) .
C) offer students a lower discount (raise the price to students) .
D) offer all customers the same discount received by the students.