Which of the Following Scenarios Best Depicts Systematic Desensitization

Which of the following scenarios best depicts systematic desensitization?

A) George stops raising his hand because the teacher usually criticizes the way he presents his answer, even when his answer is correct.
B) Ivy, who usually never forgets to turn off her headlights, forgot to turn them off because the buzzer in her car is broken.
C) Henry ignores his alarm clock each morning, despite complaints from his mother, and usually ends up missing the bus.
D) Susan has learned to relax when she gets on an airplane because she practices relaxation techniques regularly before each flight.