Option A - CORRECT.
This option is very vulnerable to the Travel Agent argument. The hotels reviewed by the book may be those that best serve its proposal, that is why his opinion is based on the review of hotels he has checked-in to. However, a review of other unpopular hotel in the two states should be looked into because they might shake the table of his comparison.
Option B - INCORRECT.
Hotels can be judged by other merits besides design, but it is obvious the Travel Agent writer is more kin about the Interior design of the most popular hotels in the state.
Option C - INCORRECT.
However, The author of the book has written other books favoring European travel is just a claim that wasn't justified in the argument.
Option D - INCORRECT.
The claim in this option is more-or-less like an advice to the Travel Agent writer so his claim about Europe and America hotel can be more justified. Hotels in other parts of the world may be better designed than those in Europe is an option the writer should consider.
Option E - INCORRECT.
Someone who hasn't been to Europe might appreciate hotel designs due to the claim of the Travel Agent writer, because most people believe in testimonies of others.