A company has 26 marketing districts across US. In each district, it collected information on the following variables: sales (in thousands), advertising dollars (in thousands), number of active accounts, number of competing brands, and a rating of market potential. The owner is interested in studying the effects of the variables on the sales volume of its products. The ANOVA summary output is below. Regression Statistics Multiple R 0.9946 R Square 0.9892 Adjusted R Square 0.9871 Standard Error 9.604 Observations 26 ANOVA df SS MS F Regression 4 176777.06 44194.26 479.10 Residual 21 1937.14 92.24 Total 25 178714.20 Coefficients Standard Error t Stat P-value Intercept 178.320 12.960 13.759 5.62001E-12 Ad Dollars 1.807 1.0810 1.672 0.109439584 Number of accounts 3.318 0.163 20.368 2.60315E-15 Number of Competitors -21.185 0.788 -26.887 9.41469E-18 Potential 0.325 0.468 0.694 0.495440936 Question: after the first individual regression coefficients test, which independent variable(s) should be removed for future analysis? Select one: a. Remove advertising dollars and rating of market potential first. b. Remove number of competing brands first. c. Remove advertising dollars first. d. Remove rating of market potential first. e. Remove advertising dollars first