For which of the following species the contribution of s electron to the shielding constant is 0.3? 

$\mathrm{He},{\mathrm{Li}}^{+}$ and ${\mathrm{H}}^{-}$are the species, the contribution of s electron to the shielding constant is 0.3.

The shielding effect is the reduction in the effective nuclear charge on the electron cloud. Due to a difference in the attraction forces on the atom's electrons.

The shielding effect is the same for elements having the same number of valence electrons in the outermost orbital.

The electronic configuration of $\mathrm{He},{\mathrm{Li}}^{+}$and ${\mathrm{H}}^{-}$is $1s^2$. As a result, the value of shielding constant for  $\mathrm{He},{\mathrm{Li}}^{+}$and ${\mathrm{H}}^{-}$is 0.3.

 Hence, option B, C and D are correct.