In a Recent Survey, Individuals Who Brushed Their Teeth Often

In a recent survey, individuals who brushed their teeth often under-reported the activity, while individuals who brushed their teeth less frequently over-reported their dental hygiene behavior. The possible cause for differences in scores could best be attributed to:

A) a true difference in the characteristic being measured.
B) differences due to situational factors.
C) differences due to temporary personal factors.
D) true differences in other relatively stable characteristics of the individuals.
E) differences due to variations in administration.