The correct answer is A) The two countries agreed on the location of borders to the east and west of Louisiana in the Adams-Onis Treaty.
The resolution between the United States and Spain that solved the boundary disputes associated with the Louisiana Purchase was "The two countries agreed on the location of borders to the east and west of Louisiana in the Adams-Onis Treaty."
The Adams-Onis Treaty was signed on February 22, 1819. sixteen years after the Louisiana Purchase of 1803. With this treaty, Spain agreed to cede the Florida peninsula to the United States and delineate the southern border with the New Spain. The United States diplomacy team had the advantage that in those years, the Spanish crown was facing some insurrections and uprisings in the New Spain territories, such as the beginning of the independence movement in México.
