command_key
command-key
commandkey
key_command
Answer is Right!
Answer is Wrong!
The correct answer is: A. command_key
The messageChannel class declares the command_key class attribute that defines the key string. This attribute is used to identify the message channel.
The command-key and commandkey options are incorrect because they do not include the underscore character. The key_command option is incorrect because it does not start with the letter c.