Professor Lyon Decided to Study Food Preferences of U

Multiple Choice

Professor Lyon decided to study food preferences of U.S. college students, so he asked his students to volunteer to participate in a lengthy survey. Based on the information given, Professor Lyon's survey results are probably invalid because:

A) he did not use an operational definition.
B) the sample selected is not representative of the larger group.
C) the selected hypothesis cannot be disproved or tested in any meaningful way.
D) he did not use independent and dependent variables.