Giving it a understandable form, argument is about a department store which mails paper coupons.
D/s observed that very less % of paper coupons are utilized by customers.
Under new strategy to reduce the amount of paper waste, D/s encourage customers to use online coupons available at its website.
Boiling it down, the D\s plans to move paper coupons to online coupons so that paper saving can be done.
After going through options, C and D are contenders.
Lets first take option C.
Whether customers who currently use paper coupons will print out the online coupons before redeeming themAccording to argument the proportion of "customers who currently use paper coupons" is very less, so whether they take print out of online coupons doesn't matter. What about larger segment of customers to which D/s mails paper coupons and coupons remains unused. The argument is more concerned about saving of waste paper coupons.
This option doesn't talk about it. Therefore, this option has no value to evaluate the plan's success.
Now option D,
How often the department store will mail flyers to customers to inform them of the availability of online coupons
Flyers: It is kind of paper template advertising the availability of online coupons.
Now rewriting the option D in two logical opposite ways as below.
Very rarely the department store will mail flyers to customers to inform them of the availability of online coupons:
Plan is successful.
Very frequently the department store will mail flyers to customers to inform them of the availability of online coupons.
Plan is unsuccessful.
Therefore, D is correct.
However, I have a doubt on use of word "mail" in two contexts of given argument. What I understood is that the word "mail" refers to forward in physical form.
Please let me know if my understanding wrong and at what point.