$B{e}^{2+}$ is isoelectronic with which of the following ions?

The correct option is B $L{i}^{+}$
Isoelectronic species are those which have the same number of electrons in them.
Number of electrons in $B{e}^{2+}$ = 2
Number of electrons in $H^{+}$ = 0;
Number of electrons in $L{i}^{+}$ = 2;
Number of electrons in $N{a}^{+}$ = 10;
Number of electrons in $M{g}^{2+}$ = 10;