2R2Y1.2 is Question content area bottom Part 1 A. the proportion of variation in Upper YY which is explained by Upper X 2 X2 but not explained by Upper X 1 X1 alone. B. the proportion of variation in Upper YY which is not explained by both Upper X 1X1 and Upper X 2X2 alone. C. the proportion of variation in Upper YY which is explained by Upper X 1X1 but not explained by Upper X 2 X2 alone. D. the proportion of variation in Upper YY which is explained by the full model