题目选项分析

Driving the steep road to the mountaintop Inca ruins of Machu Picchu is potentially dangerous and hiking there is difficult. Now the Peruvian government is installing a cable car that will make access much easier, and hence result in a large increase in tourism. However, since the presence of large numbers of tourists tends to accelerate the deterioration of a site, installation of the cable car is certain to result in harm to the ruins.

Which of the following, if true, most seriously calls into question the argument?

【选项】The cable car will replace the tour buses whose large wheels and corrosive exhaust at present do significant damage to the site.