GWD-4-14 不明白了

Q2: GWD-4-14???????????????????????????
Guidebookwriter: I have visited hotels throughoutthe country and have noticed that in those built before 1930 the quality of theoriginal carpentry work is generally superior to that in hotels builtafterward. Clearly carpenters working onhotels before 1930 typically worked with more skill, care, and effort thancarpenters who have worked on hotels built subsequently.

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

A. The quality of original carpentry in hotelsis generally far superior to the quality of original carpentry in otherstructures, such as houses and stores.
B. Hotels built since 1930 can generally accommodatemore guests than those built before 1930.
C. The materials available to carpentersworking before 1930 were not significantly different in quality from thematerials available to carpenters working after 1930.
D. The better the quality of originalcarpentry in a building, the less likely that building is to fall into disuseand be demolished.
E. The average length of apprenticeship forcarpenters has declined significantly since 1930.

我选b，答案选d，为什么啊。。没信心了