The correct answer is: B. stty intr ^c
The stty command is used to configure the terminal settings. The intr option specifies the character that will be used to interrupt a running program. The ^c character is the Control-C character, which is generated by pressing the Ctrl and C keys at the same time.
The tty command is used to get information about the current terminal. The ^c character is not a valid option for the tty command.
The stty echoe command enables the echoing of the ^c character. However, this will not change the character that is used to interrupt a running program.
The stty echo ^a command enables the echoing of the ^a character. The ^a character is the Control-A character, which is generated by pressing the Ctrl and A keys at the same time. However, the ^a character is not typically used as the interrupt key.
Therefore, the correct answer is: B. stty intr ^c