What did Robert Sutton figure out about the procedure of variolation/inoculation? Sutton figured out that smallpox was c

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What did Robert Sutton figure out about the procedure ofvariolation/inoculation?
Sutton figured out that smallpox was caused by a virus, ratherthan by bacteria or fungi.
Sutton realized that he could replace smallpox pus with cowpoxpus, creating a much safer vaccine.
Sutton figured out that the key variable in the safety ofvariolation was actually diet; a grain-rich, protein-limited dietmade you somewhat resistant to the pox virus, which is why smallpoxdisproportionately killed the wealthy.
None of the above are correct.