請依下文回答第46題至第50題。 Changes in information technology are both threatening and enhancing the ability of a business to develop long-term relationships with its customers, requiring relationship marketing. The Internet allows a customer to contact a business any time of the day or night from any location to gather information, make purchases, or obtain information on the status of accounts. This information can be (46)___  to the needs of the individual customer. This has shifted (47)___  to the customer because the Internet allows buyers to easily find information on competitive products and services. Companies can also more easily find new customers and serve existing customers by using databases to develop personal (48)___  and then targeting customers with customized information that can meet specific needs. Amazon.com, (49)___  , personalizes e-mail, customizes web pages, and offers products based on a buyer’s past purchases. Dell develops purchase portals for businesses, allowing for customized purchasing and invoicing. The Internet is (50)___  a hyper-competitive environment where information technology is used as a vital part of marketing strategy and relationship development.