Which of the Following Is True?​

Which of the following is true?​

A) ​If we can estimate h_i for each i, it means that we can proceed directly with WLS estimation.
B) ​The WLS method fails if _i is negative or zero for any observation.
C) ​The simplest way to deal with homoskedasticity in the linear probability model is to continue to use OLS estimation.
D) ​The probability p(x) depends on the error term.