The correlation between a respondent's years of education and his or her annual income is r = 0.87 Which of the following statements is true? a. 76% of the variance in annual income can be explained by respondents' years of education. b. 13% of the variance in annual income can be explained by respondents' years of education. c. 87% of the variance in annual income can be explained by respondents' years of education. d. 24% of the variance in annual income can be explained by respondents' years of education.