How to answer
This is a great time to give an example of a time when you overcame a very stressful situation.
"A couple of months ago we had a situation where one student had a complete breakdown in class. I was able to remain calm by following our program's protocol and taking the appropriate steps to ensure the safety of the student and everyone in the classroom. I am generally quite good under pressure and even better when I feel well equipped to manage the situation."
"When I feel my heart racing and my shoulders hunching, I know that I'm stressed and I tell myself to take a deep breath. Then, the first chance I get, I stretch my arms and legs out as far out as I can and think about a small treat that I'll let myself have once I get out of work. I picture it in my mind and smile. I take another deep breath and then I get through the rest of my day with a smile, knowing that whatever happens, I'll have that treat waiting for me."