Under a Totalitarian Government, Why Were Opposition Political Parties Eliminated

Under a totalitarian government, why were opposition political parties eliminated?

A) The leader would not allow elections, so they were unnecessary.
B) A single party allowed a link between the leader and the people.
C) Parliaments would take their places.
D) The courts would interpret the people's will.
E) All of the people would be in a harmonious state in an ideal environment.