请教削弱题～

kidjie1102

22. (Z3)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?

A.    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.
B.    Hotels built since 1930 can generally accommodate more guests than those built before 1930.
C.    The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930.
D.    The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
E.    The average length of apprenticeship for carpenters has declined significantly since 1930.

答案是D，为什么？
谢谢

sdcar2010

DDDDDDDDDDDDDd

If D is true, then what the author observed was simply the consequence of "whatever is the best would survive!"  So the reason to see better carpentry in old hotels is that old hotels with bad carpentry no longer exist. If this is true, the author's argument falls apart.