The Empirical Literature on the Public Sector/private Sector Wage Premium

The empirical literature on the public sector/private sector wage premium has shown that:

A) Workers in the public sector have lower earnings than workers in the private sector.
B) Workers in the public sector have earnings equal to workers in the private sector.
C) Workers in the public sector have lesser endowments of wage determining factors such as education.
D) The public sector premium, holding all other factors constant, is higher for skilled and educated workers than it is for lesser skilled workers.