Professor Myth Asked Respondents Whether or Not They Had Ever

Professor Myth asked respondents whether or not they had ever been divorced.One year later Professor Myth asked the same respondents the same question.Myth found that with repeated applications of the measure different responses were obtained for the same respondent.This means that the measuring instrument was:

A) reliable.
B) invalid.
C) unreliable or the value on the variable had changed.
D) lacking face validity.
E) inaccurate.