The correct Answers are (A):\( H' \) commutes with \( L^2 \).,(C):For a given value of principal quantum number \( n \) and orbital angular momentum quantum number \( l \), there are \( 2(2l + 1) \) degenerate eigenstates of \( H_0 \). ,(D): \( H_0 \), \( L^2 \), \( S^2 \), \( L_z \), and \( S_z \) have a set of simultaneous eigenstates,