单选题 An analyst gathered information about three economic variables. He noted that whenever variable A increased by one unit, variable B increased by 0.2 units but variable C decreased by 0.7 units. The correlation between variables A and B and the correlation between variables A and C, respectively, are closest to: Correlation between variables A and B Correlation between variables A and C A. 1.0 -1.0 B. 1.0 -0.5 C. 0.5 -1.0