To protect its frontiers, the roman empire depended on mercenaries. what is a mercenary?

a soldier who fights only for pay
a treaty with a neighboring territory
a military division that patrols borders
a neighboring tribe

Which of these was one of the most important aspects of washington's presidency a. he did not consider how his actions would affect later presidents b. he came to believe that political parties would be good for the country. c. he insisted that congress make specific rules about the duties of the president d. he did not take advantage of the opportunity to keep the power the country offered him.