For a CI calculation of the H2 ground electronic state, which of the following electron configurations will

Question:

For a CI calculation of the H2 ground electronic state, which of the following electron configurations will produce a CSF that will contribute to the wave function?
(a) (1σg)(2σg);
(b) (1σg)(2σu);
(c) (1σu)2;
(d) (1πu) (1πg);
(e) (1πu)(3σu);
(f) (1πu)2;
(g) (1πu)(2πu).