Final answer:
In the cellular stage of inflammation, migration of leukocytes to the infected area is a key component enabling the body to fight off pathogens and clean up the infected wound.
Step-by-step explanation:
The component of the cellular stage of inflammation that occurred earlier in the client's immune response to their knee wound infection would be C.) Migration of leukocytes to the area of the wound. This process, known as chemotaxis, is a part of the innate immune system's inflammatory response. Inflammatory mediators such as cytokines and histamine trigger the dilation and increased permeability of capillaries, which then allows leukocytes, including neutrophils and macrophages, to enter the injured tissues to attack pathogens and clean up cellular debris.