"A skilled architect" modifies Philip Johnson, rather than the the buildings. Eliminate A, B and C - B is tricky because of the possessive, so one may thing B should be kept in the game. I don't now how to explain the grammar rules to eliminate B, but I just know that it's wrong.
Philip Johnson designed buildingsare - I agree, thatare does make you check the sentence twice, but the sentence doesn't make sense.
Correct answer =
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Philip Johnson designed buildingsare - I agree, thatare does make you check the sentence twice, but the sentence doesn't make sense.
Correct answer =
[Reveal] Spoiler:
D
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