Because they have some properties of life!
Shore Crabs survive wave action by their shells and their strong claws. When a wave is coming they use their claws to the sand to get grip so the wave won't pull them away, they use their shells in case a rock or something hard in the waves come their way
I answer i would choose is C
You can't use it because the living cells won't be able to handle the high vacuum conditions.
Hope this helped ;)
