Choice "B" is correct. VANs are often used to route data transactions between trading partners.
Choice "d" is incorrect. Routing data "within" a company's multiple networks would normally not require a VAN. Routing data "outside" the company's multiple networks would sometimes use a VAN.
Choice "c" is incorrect. A VAN can possibly provide additional accuracy for data transmissions because a VAN may provide additional (transmission) error correction. However, data transmission has become much more dependable these days and this additional error correction has become less important.
Choice "a" is incorrect. A VAN would seldom be used to send marketing data to customers. VANs are expensive, and a cheaper means (e.g., the Internet) would most likely be used for marketing data.