Cow pox is a

Answer: Option B

Cowpox is a viral disease.
Cowpox is an infectious disease caused by the cowpox virus (CPXV). It presents with large blisters in the skin, fever and swollen glands, historically typically following contact with an infected cow.
The first description of cowpox was given by Jenner in 1798. "Vaccination" is derived from the Latin adjective vaccinus, meaning "of or from the cow".