Survey Researchers Sometimes Enclose a Dollar Bill Along with Questionnaires

Survey researchers sometimes enclose a dollar bill along with questionnaires in order to increase the odds that recipients will complete and return them.This technique often works because

A) the monetary compensation puts respondents in a good mood.
B) a dollar bill is usually a strong enough motivator for filling out a questionnaire.
C) respondents decide that their time is worth less than a dollar.
D) respondents often mindlessly follow the reciprocity norm.
E) the dollar bill serves as a subtle cue that the survey is important.