A Distant Source of Light Is Emitting the Balmer Series

A distant source of light is emitting the Balmer series, and the source of light is moving toward the Earth at a rate of 10 km/s. The wavelength of the 656.28-nm line will be observed at

A) 656.24 nm.
B) 656.26 nm.
C) 656.28 nm.
D) 656.30 nm.
E) 656.32 nm.