As a construction material, bamboo is as strong as steel and sturdier than concrete. Moreover, in tropical areas bamboo is a much less expensive construction material than either steel or concrete and is always readily available. In tropical areas, ttherefore, building with bamboo makes better economic sense than building with steel or concrete, except where land values are high. Which of the following, if true, most helps to explain exception noted above? ['Bamboo is unsuitable as a building material for multistory buildings.', 'In order to protect it from being damaged by termites and beetles, bamboo must be soaked, at some expense, in a preservative.', 'Bamboo growing in an area where land values are increasing is often cleared to make way for construction.', 'Buildings constructed of bamboo are less likely to suffer earthquake damage than are steel and concrete buildings.']