Clothing acts as insulation to keep body heat in. Bryan wants to know whether a wool sock or a cotton sock will be better at keeping heat in. He puts the wool sock around cup 1 and the cotton sock around cup 2 and then fills both cups with hot water. How can he tell which sock is a better insulator? A. measure the temperature of the air B. measure the temperature of each sock by itself C. measure which cup of water stays hot the longest D. measure how long it takes to drink the water