Question ID:PT89 S4 Q18 Passage:Certain changes in North American residential architecture after World War II are attributable mainly to the increased availability and affordability of air-conditioning. Soon after World War II, many builders found that air-conditioned houses lacking the high ceilings and thick walls that traditionally kept residents cool during extreme heat generally sold well. Stem:Which one of the following, if true, most seriously weakens the argument? Correct Answer Choice:CChoice A:High ceilings and thick walls enable houses to withstand many types of severe weather that are common in North America. Choice B:Thin-walled, low-ceilinged houses are more costly to heat in winter than thick-walled, high-ceilinged houses. Choice C:Houses with low ceilings and thin walls were prevalent in North America even where there was no demand for residential air-conditioning. Choice D:Thin walls allow cool, air-conditioned air to escape more readily from houses than do thick walls. Choice E:Soon after World War II, new thermal-insulating technology was widely applied in house building.