The idea that the rulers of europe whom napoleon had driven from power should be resorted to their thrones was based on the principle of?

Plz ive been stuck on this question forever. in 1753 george washington was sent on a mission to a. build a fort at the point where the allegheny and monongahela rivers form the ohio river. b. attack the french at fort duquesne. c. attack the french at fort neccessity. d. deliver a message to the french demanding that they leave the ohio river.