After a snow storm, the roof on one house, H1, isuniformly covered by snow, whereas at the house next door, H2, the snow has completely melted off. A likely reason for this is:
a. House 1's roof is larger
b. House 1's insulation has a higher thermal conductivity thanHouse 2's
c. The interior of House 1 is hotter than the interior ofHouse 2
d. House 1 has a thicker layer of the same insulation as House2