Calculate the wavelength emitted during the transition of electron in between two levels of $Li^{+2}$ ion whose sum is 4 and difference is 2.

Question

$\begin{array}{1 1}(a)\;1.14\times 10^{-2}cm&(b)\;2.3\times 10^{-6}cm\\(c)\;1.14\times 10^{-6}cm&(d)\;2.4\times 10^{-3}cm\end{array}$