Why Are Classification Questions Typically Placed at the End of the Questionnaire

Multiple Choice

Why are classification questions typically placed at the end of the questionnaire?

A) because they are not important
B) because they are used to screen respondents
C) because they typically seek information of a more personal nature that may affect the nature of responses to subsequent questions or even result in non-participation if they are asked early in the questionnaire
D) because this enable respondents to skip irrelevant questions that appear before them, but the researcher will still gather information on the research topic
E) because they might confuse respondents if they were placed early in the questionnaire