Simplify the following text for a Grade 5 native English-speaking person.
Original: D.C. United is an American professional soccer club based in Washington , D.C. which competes in Major League Soccer ( MLS ) , the top professional soccer league in the United States of America and Canada .
Simplified: D.C. United is a Major League Soccer league soccer ( or football ) team that plays in Washington , D.C. in the United States .