Q33. When $\psi _ { \mathrm { A } }$ and $\psi _ { \mathrm { B } }$ are the wave functions of atomic orbitals, then $\sigma ^ { * }$ is represented by:\\
(1) $\psi _ { \mathrm { A } } + 2 \psi _ { \mathrm { B } }$\\
(2) $\psi _ { A } - \psi _ { B }$\\
(3) $\psi _ { \mathrm { A } } + \psi _ { \mathrm { B } }$\\
(4) $\psi _ { A } - 2 \psi _ { B }$