Calculate the Wavelength, in Nanometers, of the Light Emitted by a Hydrogen

Calculate the wavelength, in nanometers, of the light emitted by a hydrogen atom when its electron falls from the n = 7 to the n = 4 principal energy level.Recall that the energy levels of the H atom are given by E_n = -2.18 × 10^-18 J(1/n²)

A) 9.18 × 10^-20 nm
B) 4.45 × 10^-20 nm
C) 2.16 × 10^-6 nm
D) 2.16 × 10³ nm
E) 1.38 × 10¹⁴ nm