Colleges often rely heavily on raising money for an "annual fund" to support operations. Alumni are typically solicited for donations to the annual fund. Studies suggest that the graduate's annual income is a good predictor of the amount of money he or she would be willing to donate, and there is a reasonably strong, positive, linear relationship between these variables. In the studies described:A. Size of donation to the annumal fund is the response variable. B. All of the answer options are correctC. annual income is an explanatory variableD. The correclation between annual income and size of donation is positive