Which of the following statements about the correlation coefficient are true?
I. The correlation coefficient and the slope of the regression line may have opposite signs.
II. A correlation of 1 indicates a perfect cause-and-effect relationship between the variables.
III. Correlations of +0.87 and - 0.87 indicate the same degree of clustering around the regression line.
A. I only
B. II only
C. III only
D. I and II
E. I, II, and III