Suppose that you are conducting market research at a regional mall in your city. The survey you are administering contains some relatively personal questions that some consumers might be reluctant to answer. As a result, you decide to select passers-by whom you believe are most likely to agree to answer your questions. Such an approach helps to ensure that all surveys will be completed and that questions will be answered in an unbiased manner. Nonetheless, it may come with a cost. Of the following statements, which is not a potential problem associated with this approach? a. It might unexpectedly impact the "representativeness" of the sample.
b. All the answer options are potential problems.
c. It is likely to decrease the response rate.
d. It violates the underlying principles inherent in "probability sampling" techniques.
e. It could negatively influence the validity of the research study.