What command is used to hand up a MODEM when using the “AT Answer Command set”? A. ATZ B. ATD C. ATR D. ATH E. None of the above

The correct answer is D. ATH.

The AT command set is a standard set of commands used to control modems. The ATH command is used to hang up a modem. The other options are not valid AT commands.

ATZ is used to reset the modem. ATD is used to dial a phone number. ATR is used to get the modem’s response.