Answer: Sales promotion ; viral marketing
Explanation: Sales promotions may be explained as technique used by businesses to appease and lure their target market into buying and using their product through the use of appealing incentives such as cost or slash sales, free coupons or discount on purchase and various promotions which are normally not attached to buying the product. Viral marketing in the other hand simply employs the use of internet technology such as mail and social media in the spread of a business campaign and information. It is termed viral marketing as information dissemination can be so rapid when done via this channel.