Answer: Option C
Answer: (c)
RBINet is a communication software, developed in ‘C’ and available for both DOS and UNIX machines. It allows free format messaging and file transfer on the existing BANK NET infrastructure with the help of UNIX servers installed at the 4 NCCs.
Each RBINet user interacts with the local UNIX server through PADs connected to the X.25 switch.  The UNIX servers in turn communicate with each other using TCP/IP over the X.25 protocol.
The software allows free format messaging without any restrictions on the length of the message, enables file transfer of both ASCII-text and Binary (spreadsheets, databases, programs etc.) files, facilitates dial-up access, and has security features such as end-to-end encryption, audit trail, etc.