Ali sees an advertisement offers to give a free bag for a purchase of 3 storybooks. This offer is by World of Book Sdn. Bhd, a company selling reference book. Ali goes to the store & buys 3 storybooks. Then he claims the free bag from the cashier. The cashier refuses to give him the bag. Reason is it is just as advertisement to promote. Based on the contract law you have learned, discuss whether Ali can claim the free bag. Provide case law.