Why Are Many Marketers Shortening the Time in Which a Coupon

Why are many marketers shortening the time in which a coupon can be redeemed?

A) to track response rates
B) to increase introductory sales
C) to create a greater sense of urgency to redeem the coupon
D) to respond to claims that coupons adversely affect consumer behavior
E) to limit the use of on-pack coupons