The result of the growth of independent voters since 1960s is:
D)Political parties do not worry about the growth of moderate voters as evidence of the extreme polarization in our society today.
Step-by-step explanation:
There has been a recent surge in favoritism in party politics with increasing number of voters being polarized and voting for the party that has the public perception of representing what they believe in and not looking at the specific policies of the politicians who are running in that particular period.
So there is a surge of people who do not vote moderate and the political parties understand that the moderates do not count for enough vote share and most of them end up taking one side or the other any way.