Company X manufactures two radiator models: Nice'N'Warm and Some Like It Hot. John has the Nice'N'Warm model in his bedroom, and Jane has the Some Like It Hot model in her bedroom. Last winter, John and Jane turned on their radiators to maximum every night at 22:00 and turned them off at 07:00. The temperature in Jane's bedroom was eight degrees warmer than the temperature in John's bedroom. Clearly, the Some Like It Hot model is more effective than the Nice'N'Warm model.
Which of the following is an assumption underlying the argument above?
A. Jane's bedroom is smaller than John's bedroom.
B. The price of Nice'N'Warm is higher than the price of Some Like It Hot.
C. John and Jane live in areas with the same climate.
D. John is as sensitive to cold as Jane is.
E. Company X manufactures only two radiator models.