Which of the situations below probably does not have a lurking variable operating in some way? Choose the best answer. A. Small dogs bite more people than large dogs nationwide, but in both rural areas and urban areas, large dogs are more likely to bite people. B. When sales of cold medication go up, sales of ice cream go down. C. Beaches with more sand than rocks tend to be older. D. Towns that have more teachers have higher sales of floor wax and cat litter. E. Neighborhoods with more station wagons tend to have more playgrounds