A salesperson who would like to get as many people as possible to view his open house may use which of the following sales promotions to induce sales traffic?
a) Offer everyone who walks through the chance to buy a ticket to a lottery of the house if it does not sell in 30 days.
b) Offer a free refrigerator magnet to each person who walks through the house.
c) Give the fifth and the fiftieth customers a gift certificate.
d) Sell raffle tickets for a chance to win a plasma television set.