According to Molecular Orbital Theory, Which One of These Species $$\mathrm { He } _ { 2 } ^ { + }$$

According to molecular orbital theory, which one of these species does not exist?

A)
$$\mathrm { He } _ { 2 } ^ { + }$$
B)
$$\mathrm { H } _ { 2 } ^ { + }$$
C)
$$\mathrm { H } _ { 2 } ^ { - }$$
D)
$$\mathrm { H } _ { 2 } ^ { 2 - }$$
E) CH₄