An economist conducted a study of the possible association between weekly income and weekly grocery expenditures. The particular interest was whether higher income would result in shoppers spending more on groceries. A random sample of shoppers at a local supermarket was obtained, and a questionnaire was administered asking about the weekly income of the shopper's family and the grocery bill for that week. The gender of the shopper was also obtained. A least-squares line was obtained for the data and the residual sum of squares was obtained. The residual sum of squares measures the:
A. sum of squared distances of the response variable values to the mean of the response variable.
B. sum of squared distances of the explanatory variable to the mean of the explanatory variable.
C. sum of the squared distance between the observed response and the corresponding predicted value on the least squares line for cach point.
D. None of the answer options is correct.