The correct answer is C) He was an isolationist.
All of the following were true about Alfred Thayer Mahan EXCEPT "he was an isolationist."
Alfred Thayer Mahan (1840-1914) was a US navy officer, renown for his bright mind and great strategies. He graduated from the prestigious United States Naval Academy, in Annapolis, Maryland. He published the book "The Influence of Sea Power Upon History: 1660-1773" in 1890. In the ideas expressed in his book after observing the British Royal Navy, he urged the government of the United States to invest in a better and bigger navy in order to protect the country and control the seas.