Intranets: a. are based on mainframe technology. b. provide the platform on which a firm builds its information systems. c. are
multiple networks joined together. d. are typically used to communicate with the business's trusted vendors. e. use Internet technology for a private company network.
Intranet is the private network that is created for sharing information and data ,handle computing facilities, sharing files etc through internet service within a organization. Members of the company can access this technology for performing activities on the network.
Other options are incorrect because numerous networks are not linked ,does not share information outside organization, does not act as information system's base and neither is linked with mainframe technology.