When used as data for sociological analysis by a researcher not involved in the original data collection, national opinion polls and Census data are considered

A) invalid.
B) unreliable.
C) secondary data.
D) primary data.

Secondary Data

This refers to data that has been previously collected and analyzed by someone else, and is then used for a new research project.

National Opinion Polls

Surveys conducted to assess the public's views or opinions on various topics at a nationwide level.

Census Data

Statistical data about a population and its characteristics, usually collected by a government.