What Led to the Development of a New Theory of Public

What led to the development of a new theory of public opinion?

A) New research rejected the old premise that citizens' beliefs had to be internally consistent, stable, and based on a rationale that citizens could explain.
B) Research on surveys from the 1960s uncovered serious mathematical errors in earlier published research from the 1950s.
C) Increased educational opportunities changed how people thought about politics.
D) New survey technologies made public opinion research easier to conduct.
E) As candidates and politicians became more dependent on polls, additional research was needed to understand how best to measure public opinion.