这道逻辑题弄不懂

Guidebook writer:  I have visited hotels throughout the country and have noticed that in those built before 1930 the quality of the original carpentry work is generally superior to that in hotels built afterward.  Clearly carpenters working on hotels before 1930 typically worked with more skill, care, and effort than carpenters who have worked on hotels built subsequently.

Which of the following, if true, most seriously weakens the guidebook writer’s argument?

1. The quality of original carpentry in hotels is generally far superior to the quality of original carpentry in other structures, such as houses and stores.
2. Hotels built since 1930 can generally accommodate more guests than those built before 1930.
3. The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930.
4. The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
5. The average length of apprenticeship for carpenters has declined significantly since 1930

答案是D，但是我觉得答案恰恰支持问题中的结论

请大虾指教

Guidebook writer的统计知识非常差，抽样的时候犯了典型的survivorship bias，因为只有那些好的building才可能保留下来（less likely to be disused and demolished，被弃用并摧毁的可能性小)，D指出the writer现在看到的是1930年之前建筑物中的少量精品而已。