President Washington was worried about the southern border with Spain because B. the stability of American trade taking place in New Orleans.
When Washington was President, Spain controlled Florida and the New Orleans area.
This was a problem to the new president because a lot of U.S. trade went through New Orleans and hostility with the Spanish could affect that.
Find out more on Spanish control of New Orleans at https://brainly.com/question/8177373.
#SPJ1