A three-variable multiple regression establishes an estimated multiple regression equation in such a way that a) all the estimates derived from it fall on a surface that is called the regression plane b) all the estimates derived from it fall on a surface that is called the regression plane, which is positioned among the sample points in such a way as to minimize the sum of the square horizontal deviations between these sample points and their associated estimates c) all the estimates derived from it fall on a surface that is called the regression plane, which is positioned among the sample points in such a way as to minimize the sum of the squared horizontal deviations between these sample points and their associated estimates, all of which lie on this plane d) All of the above