How does inflammation develop?

a. During inflammation, all blood cells retreat from the site of infection in order to protect the circulatory system from pathogen infection.
b. Inflammation is an ongoing condition in the human body, part of the way that the innate immune system can respond immediately to an infection.
c. When an infection occurs, an immediate inflammatory response occurs as soon as pathogens enter the body.
d. Inflammation is induced by molecules such as cytokines and histamine that are produced by various host cells in response to pathogens at the site of injury or infection.