In the event of a fire, what is the best way to determine if a door is safe to open?

The answer is C - Check it for heat with the back of your hand. You can rule the others out and get your answer by simply going by logic. To check for heat you do not A - Kick the door open, or D - Grab the handle. That isn't checking the heat at all, so now we have B and C. Do you use your forearm or the back of your hand? You use the back of your hand. It's the smallest part of you body in this case the most accessible. You might be wearing a longer shirt, for example. The hand is also easiest to move towards the handle and can rotate better. Also, if there is no heat, or very little, one may successfully and quickly open the door. A split second timing can mean the difference between life and death.

Your answer is true.