Answer:
Option B.
Moving away from each other.
Step-by-step explanation:
The spectra emitted by the objects in the solar system refer to the electromagnetic waves that are emitted from the object.
When viewed from the earth the shifting of the spectra to longer wavelengths suggest that the objects are not in the same position as they used to be. This is because the time the waves take to reach the earth have changed, thus suggesting also a change in their position.