Correct Answer - D
We know that, the wavelength of emited radiation is givne by
`(1)/(lambda)R((1)/(n_(1)^(2))-(1)/(n_(2)^(2)))=RxxK"where,"K=(1)/(n_(1)^(2))-(1)/(n_(2)^(2))`
For `lambda_("max")` K should be minimum.
Which corresponds to ` n_(1)=3,n_(2)=4` So, transition takes place between n=4 and n=3 states.