NSSF, the National Shooting Sports Foundation, Tested the Effectiveness of Its

NSSF, the National Shooting Sports Foundation, tested the effectiveness of its Original Outdoor Challenge ad campaign with selected gun retailers in California, Oklahoma, and New York. The results were promising as all the retailers increased their sales and received more customer interest in shooting sports. NSSF plans a national rollout for the campaign. The gun retailers in California, Oklahoma, and New York were a:

A) probability sample.
B) universe.
C) test market.
D) non-probability sample.
E) target market.