I just need some paragraphs about vaccines and it’s history

First vaccines

Edward Jenner invented a method to protect against smallpox in 1796. The method involved taking material from a blister of someone infected with cowpox and inoculating it into another person's skin; this was called arm-to-arm inoculation.

We begin our history of vaccines and immunization with the story of Edward Jenner, a country doctor living in Berkeley (Gloucestershire), England, who in 1796 performed the world's first vaccination. Taking pus from a cowpox lesion on a milkmaid's hand, Jenner inoculated an eight-year-old boy, James Phipps.

The smallpox vaccine was the first vaccine to be developed against a contagious disease. In 1796, the British doctor Edward Jenner demonstrated that an infection with the relatively mild cowpox virus conferred immunity against the deadly smallpox virus.

The smallpox vaccine was the first vaccine to be developed against a contagious disease. In 1796, the British doctor Edward Jenner demonstrated that an infection with the relatively mild cowpox virus conferred immunity against the deadly smallpox virus.

explanation:

on disadvantage of hydroelectric power is the cost. another disadvantage of using hydroelectric power is finding a water source powerful enough to harvest hydroelectric power.

c should be the answer