"The Star-Spangled Banner" is the U.S. of America National Anthem. Was written on September 14, 1814, by the lawyer an amateur poet Francis Scott Key. Key described in the song what he witnessed the bombardment of Fort McHenry by British ships of the Royal Navy in Baltimore Harbor during the Battle of Baltimore in the War of 1812.
When he endorses: "hirelings and slaves" Key probably felt that sailors were being mistreated by their captain. Besides many of the British soldiers were forced into war.
The answer to this question is c.
