In which of the following pairs of molecules/ions, both the species are not likely to exist?

Options

A. `H_(2)^(+), He_(2)^(2-)`
B. `H_(2)^(-), He_(2)^(2-)`
C. `H_(2)^(2+), He_(2)`
D. `H_(2)^(-), He_(2)^(2+)`