When mary lynn went to the grocery store last week, she took with her several coupons she had received in the mail that week. while at the store, mary lynn was offered samples of several food items and she actually bought a few of those, using the in-store coupons. she also bought a particular brand of toothpaste, because the tube came with a free toothbrush. mary lynn is taking advantage of:
a) sales promotion.
b) advertising.
c) publicity.
d) viral marketing.