Which of the Following Constitutes a False Alarm in Signal

Which of the following constitutes a false alarm in signal detection theory?

A) You hear your teakettle whistling, and you turn off the stove.
B) You are focused on studying, and you do not notice your roommate leaving for dinner.
C) You turn off the radio to answer your phone, but the phone is not ringing.
D) You expect your nephew to cry when he falls, but he doesn't.