The correct answer is A) Arkansas.
The expedition under Stephen H. Long mistook the Arkansas River for the Red River and abandoned its mission in 1820.
Throughout the history of the United States, many expeditions were organized in order to explore new lands and the recognition of others. Major Stephen H. Long led one of these expeditions in 1819-20. He was a Topographical Engineer. He led the people that embarked on the ship Western Engineer in the Port of Pittsburg, Pennsylvania. It was on July 24, 1820, that they crossed the Arkansas River down south, and on the 28th, he realized he mistook the Arkansas River for the Red River and abandoned its mission.