In the Emission Spectrum of Hydrogen the Brackett Series of Lines

Multiple Choice

In the emission spectrum of hydrogen the Brackett series of lines corresponds to transition of electrons from the excited states to the n₁=4 orbit. What is the wavelength of the energy line n₂=9 in the Brackett series?

A) 1350 nm
B) 5.50 × 10⁵ nm
C) 1.09 nm
D) 1820 nm
E) 0.0123 m