You See a Galaxy in Which the H $\alpha$ Line (Rest Wavelength= 656

Multiple Choice

You see a galaxy in which the H $\alpha$ line (rest wavelength= 656.3 nm) is observed at a wavelength of 756.3 nm. What would be the observed wavelength of a particular helium line, which has a rest wavelength of 1,083 nm?

A) 1,083 nm
B) 1,183 nm
C) 1,248 nm
D) 1,440 nm
E) 3,142 nm