Which Statements Below Concerning U.S. Marshals Is True

Which statements below concerning U.S. marshals is true?

A) Once the "Wild West" was tamed, the U.S. marshals became obsolete.
B) They are considered the "beat cops" of federal law enforcement.
C) They are the top law enforcement official in county government.
D) They were originally known as bobbies and were created by the Metropolitan Police Act.
E) They are federal law enforcement officials originally appointed to handle duties in western territories .