What does the square of the correlation coefficient, r squared, tell us about a best-fit line? Question content area bottom Part 1 Choose the correct answer below. A. It tells us the variation of the slope of the best-fit line. For example, if r squaredequals0.9, or 90%, then the best-fit line slope is 90% of the real slope. B. It tells us the percentage of the variation that is accounted for by the best-fit line. For example, if r squaredequals90, or 90%, then 90% of the variability is accounted for by the best-fit line, but 10% is not. C. It tells us the proportion of the variation that is accounted for by the best-fit line. For example, if r squaredequals0.9, or 90%, then 90% of the variability is accounted for by the best-fit line, but 10% is not. D. It tells us the accuracy of the slope of the best-fit line. For example, if r squaredequals0.9, or 90%, then the best-fit line slope is at least 90% accurate