The correct alternative would be letter B) The Great Plains.
The Great Plains is an area that embraces the states of Kansas, Nebraska, North Dakota, and South Dakota, as well as parts of Colorado, Iowa, Minnesota, Montana, New Mexico, Oklahoma, Texas, and Wyoming.
Not only the US, but it also embraces a part of Canadian Provinces of Alberta, Manitoba, and Saskatchewan.
They're so big in extension that pretty much anyone going from one side of the country to the other would bypass the Great Plains, and for that reason, they're the correct answer.
