Define the term 'sepsis'.

Sepsis is defined as a life-threatening organ dysfunction that arises as a result of the body’s extreme response to an infection. When an infection occurs, the immune system typically helps to eliminate the pathogens. However, in sepsis, the body’s response goes haywire, leading to widespread inflammation and, ultimately, potential failure of organs such as the kidneys, liver, or lungs. This dangerous cascade can quickly escalate and lead to septic shock, which is characterized by dangerously low blood pressure and multiple organ dysfunction.

In contrast, the other options relate to different medical conditions. An allergic reaction to medication does not involve an infectious process or organ dysfunction in the same way sepsis does. A bacterial infection in the lungs may lead to pneumonia but does not automatically indicate sepsis unless the body’s response causes organ dysfunction. Lastly, elevated blood pressure, while it can indicate a health issue, is not a definition of sepsis and does not encompass the systemic effects of an overwhelming infection. Thus, the correct understanding of sepsis encompasses the severe body response to infection leading to potential organ failure, making option C the accurate definition.