Whenever John Shops for Groceries, He Gives an ID Card

Multiple Choice

Whenever John shops for groceries, he gives an ID card to the clerk, who scans the number. Then the scanner records every purchase-including brands, sizes, prices, and any coupons used. John is most probably a

A) licensed purchaser.
B) consumer panel member.
C) market researcher.
D) focus group leader.
E) opinion leader.