The following regression model investigates factors affecting the probability of an individual's mortgage loan approval:

= 0 + 1 + 2 + 3 +

where is a dummy variable equal 1 if a mortgage loan to an individual was approved;

is a dummy variable equal 1 if the applicant was white;

is a dummy variable equal 1 if the applicant was married;

and is the individual's income

Which of the following statements is FALSE about the above regression model?

Select one:

a. To estimate the regression, Weighted Least Squares (WLS) is preferred to using robust standard errors because the model is likely to suffer from the omitted variable bias problem

b. OLS estimators of the parameters in the model are not the Best Linear Unbiased Estimators (BLUE)

c. We can't use the t-test to test whether the coefficient of married is significant or not

d. The conditional variance of the error term is not constant and thus the F-test is invalid even if the sample size is large