Option (A) is correct. According to the provided context, Edward Jenner coined the word 'vaccine' and was the one who injected the cow pox virus to confer protection against small pox. The text defines vaccination as 'the process of injection and administering vaccines'. Since Jenner pioneered this process, he is credited with the invention of vaccination. The context clarifies that while Louis Pasteur coined the specific term 'vaccination' in 1881, the invention of the method itself belongs to Jenner.