Pollsters Have to Be Concerned About Ideological Self-Identification in Polls

Pollsters have to be concerned about ideological self-identification in polls because

A) many Americans do not know what liberalism and conservatism mean.
B) many Americans do not feel the need to be ideologically consistent.
C) some respondents will hide what they think to be socially unacceptable self-identifications.
D) the desire to hide self-identifications might inflate responses of "don't know" or "moderate."
E) All of the above.