What is sterilization​

Sterilization refers to any process that removes, kills, or deactivates all forms of life and other biological agents like prions present in a specific surface, object or fluid, for example food or biological culture media. 

there's more in WIKI PEDIA!

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Sterilization refers to any process that removes, kills, or deactivates all forms of life and other biological agents like prions present in a specific surface, object or fluid, for example food or biological culture media.

i think it's letter a.

answer carbon and three oxygen atoms;