Нужно составить вопросы. the telephone and the telegraph are means of communication

1. Are the telephone and the telegraph means of communication? (общий вопрос )
2. What are the means of communication? ( вопрос к подлежащему )
3. The telephone and the telegraph are means of communication, aren't they? ( альтернатиный вопрос)
4. What kind of means are the telephone and the telehraph? (специальный вопрос )