What Is Transmission Control Protocol/Internet Protocol (TCP/IP)

What is transmission control protocol/Internet protocol (TCP/IP) ?

A) Software that prevents direct communication between a sending and receiving computer and is used to monitor packets for security reasons.
B) A standard that specifies the format of data as well as the rules to be followed during transmission.
C) A simple network protocol that allows the transfer of files between two computers on the Internet.
D) A standard Internet protocol that provides the technical foundation for the public Internet as well as for large numbers of private networks.