A "Contingency Question" in a Questionnaire Refers To

A "contingency question" in a questionnaire refers to:

A) a question that can be dropped if the interview is taking too long.
B) a question that is revised or dropped because it is shown to be ambiguous in a pretest.
C) an open ended question that will have to be coded by the investigator during data analysis.
D) a question that a respondent may or may not answer depending on their response to a previous question.