The correct answers are A) the United States, B) Spain, and C) France.
The three countries that controlled the Louisiana territory during this period were the United States, Spain, and France.
The United States purchased the Louisiana territory in on April 30, 1812. After months of negotiations ordered by United States President Thomas Jefferson, the US accepted to pay France $11,250,000 for the Louisiana territory. The US acquired 850,000 square miles of new land for the country.