I believe the answer is A, Pollution of the environment, hope this helps :)
Answer:
Correct answer is (D) He created beautiful natural spaces in cities, including Central Park in New York City
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Explanation:
Option D is a correct answer as Olmstead as in 1857 he won the competition to design the Central Park, and after that he was the main architect during its construction.
A is not correct as the first steel-framed skyscrapers in New York was Bradford Gilbert (Tower Building).
B is not correct as this is contributed to Elisha Otis.
C is not correct as Brooklyn Bridge was designed by John A. Roebling, and constructed by his son Washington.
Hitlers form of attack that used tank divisions supported by air attacks was called phony war. Hope this helps ! (:
