Growing crops on mountainous terrain can make farming very difficult. This kind of problem is what started the idea of terraced gardens where parts of the mountain were flattened out kind of like steps in order to increase surface area and make it easier to farm.
I'd say it is B, but I'm not entirely sure.
The Influence of Sea Power upon History. The Influence of Sea Power Upon History: 1660–1783 is a history of naval warfare published in 1890 by Alfred Thayer Mahan. ... Its policies were quickly adopted by most major navies, ultimately leading to the World War I naval arms race.