Select the transition which will have the minimum wavelength in a hydrogen atom: 

answer

$\mathrm{E}=\frac{\mathrm{hc}}{\lambda }\Rightarrow \mathrm{E}\propto \frac{1}{\lambda }$

i.e. for smallest wavelength, we need the largest energy difference.

The largest energy difference is between states one and two which is 10.2 eV.