Answer :
"Washington feared politicians would hold greater allegiance to their factions or parties than to the nation as a whole" is the one reason among the following choices given in the question that George Washington oppose the formation of political parties. The correct option among all the options given in the question is option "b".
George Washington opposed political parties because he thought they threatened to weaken liberty. Washington worried that parties would result in political factions that could control individuals. He also thought political parties could divide the nation.