The correct answer is (a) interpret as command (IAC) escape character has to be used
Best explanation: The client must look at each byte that arrives and look for IAC escape character. If IAC is found, the client moves on to look for any other code or IAC. If the next byte is IAC – a single byte is presented by the client to the terminal. If IAC is followed by any other code than IAC, the client interprets this as a command.