Given the Simplex Tableau for the Optimal Primal Solution

Given the simplex tableau for the optimal primal solution

A) the values of the dual variables can be found from the c_j -z_j values of the slack/surplus variable columns.
B) the values of the dual surplus variables can be found from the c_j - z_j values of the primal decision variable columns.
C) the value of the dual objective function will be the same as the objective function value for the primal problem.
D) each of the above is true.