a radio station chose 1000 at random within it's broadcast area. it sent a survey to be filled out that asked questions about radio habits. the survey was to be filled out and sent back in to the radio station. indentify a problem with the study.

A.) The relationship between two variables implies one causes the other.
B.) A nonresponse occurred.
C.) Some of the sample data are missing.
D.) The conclusion is based on a voluntary response sample.