A mail-order retailer of low-cost novelty items is receiving an increasing number of complaints from customers about the wrong merchandise being shipped. The order code for items has the format The major category is ww, xx is the minor category, yy identifies the item, and zz identifies the catalog. In many cases, the wrong merchandise was sent because adjacent characters in the order code had been transposed. The best control for decreasing the number of orders with the wrong merchandise is to:
A. equire customers to specify the name for each item they order
B. dd check-digits to the order codes and verify them for each order
C. eparate the parts of the order code with hyphens to make the characters easier to read
D. se a master file reference for all order codes to verify the existence of items