Doubly$-$ionized lithium is a hydrogen$-$like ion, in which the nucleus with charge $3$e is orbited by a single electron. What wavelength light would be emitted from Li$++$ as the electron dropped from the n $=4$ to the n $=3$ orbit? A$)16\mathrm{.}9$m B$)1\mathrm{.}88$m C$)470$ nm D$)208$ nm E$)91$ nm