Answer:
C. Cryosphere
Step-by-step explanation:
The definition for Cryo is:
Involving extreme Coldness and etc.
There are studies done on Cyro Freezing the body to preserve the body until there is a cure for a deadly disease. They do this as well to try to live in the future. Our technology hasn't been able to get the people alive yet, but when we do.
If you ever need to think of "Cryo" just think of Cryo Freezing.