Imagine you regressed earnings of individuals on a constant, a binary variable (“male”) which takeson the value 1 for males and is 0 otherwise, and another binary variable (“female”) which takes onthe value 1 for females and is 0 otherwise. because females typically earn less than males, youwould expecta) the coefficient for male to have a positive sign, and for female a negative sign. b) both coefficients to be the same distance from the constant, one above and the other below. c) none of the ols estimators exist because there is perfect multicollinearity. d) this to yield a difference in means statistic.