Regarding the Length of Questionnaires to Be Used in Survey

Regarding the length of questionnaires to be used in survey research,which of the following statements is most accurate?

A) Including a large number of items on the survey assures that you will get useful data for all of your trouble.
B) Keeping the survey short makes it more likely people will be willing to complete it.
C) A relatively lengthy survey communicates your seriousness about the research endeavor so people will be more willing to complete it.
D) Shorter surveys produce data that are ambiguous and therefore not useful.