How did the United States benefit from Thomas Pickney's treaty?

This Treaty defined the border with Spain and the US

Explanation:

The Treaty was signed and defined the US territorial debates that were ongoing in between the countries. It is considered a diplomatic success for the US and garnered US citizens access to travel the Mississippi River freely and access trade routes from the port in New Orleans in Spanish control.

i think the answer is c, rivers.

explanation:

sometimes, borders fall along natural boundaries like rivers or mountain ranges. for example, the boundary between france and spain follows the crest of the pyrenees mountains. for part of its length, the boundary between the united states and mexico follows a river called the rio grande. the borders of four countries divide africa’s lake chad: niger, chad, cameroon, and nigeria.