Explanation: nothing thats it.
the Andromeda Galaxy and the Milky Way
just took the test and got it right
Think of it like this; a car passes by you, as it goes, it's horn gets louder, and then starts to become quieter as it moves further away. Redshift works the same way. When an galaxy starts to move away from Earth, it's light appears to be redder. (If it was moving closer to Earth, it would most likely become bluer.)
redshift is the answer
The galaxies are moving away from Earth because the fabric of space itself is expanding.
option Aᕦ( ᐛ )ᕡ
I think c is correct due to reason given by you