John Is on Probation at Work Because He Has Been

John is on probation at work because he has been blowing up at customers when he perceives that they are pushing him around. He found that when he takes his pain medication left over from an old injury, the customers' rudeness doesn't bother him. As a result, he is much more relaxed at work and in fact was complimented on his patience. What is this an example of?

A) controlling emotions
B) taking direct action
C) reframing the problem
D) finding motivation