For Most of the Half Century After World War II

For most of the half century after World War II, Japan could best be described politically as

A) a democratic state where two major parties dominated the political process, sharing power alternately.
B) a constitutional monarchy wherein the emperor chose the prime minister and the cabinet subject to ratification by the Diet.
C) a largely authoritarian society where the genro oligarches ruled according to the 1947 constitution.
D) a democratic state where one party held power throughout the period.
E) an Asian-style "people's republic."