Suppose That, from a Stationary Spaceship, You Identify a Source

Suppose that, from a stationary spaceship, you identify a source of hydrogen (H_α) light on the surface of a planet that has a very strong gravitational field. When you observe an equivalent H_α light source on your spaceship, the wavelength is 656.3 nm. How long is the wavelength you measure when you look at the light source on the planet?

A) shorter than 656.3 nm
B) the same wavelength of 656.3 nm, but the frequency of the light appears lower
C) 656.3 nm, the same as your light source, but the source appears very faint because the radiation has been weakened by the gravity field
D) longer than 656.3 nm