If You Find That the H-Alpha Line in a Star's

Multiple Choice

If you find that the H-alpha line in a star's spectrum occurs at a wavelength of 656.45 nm, what is the star's radial velocity? Note that the rest wavelength of this line is 656.30 nm.

A) 150 km/s away from you
B) 150 km/s toward you
C) 350 km/s toward you
D) 70 km/s away from you
E) 70 km/s toward you