Empyema is defined as an

Choice A reason: Infection in the blood is not empyema. It is sepsis, which is a life-threatening condition that occurs when the body's response to infection causes tissue damage, organ failure, or death. Choice B reason: Infection in the pleural space is empyema. It is a collection of pus in the space between the lungs and the chest wall, usually caused by a bacterial infection that spreads from the lungs or the chest cavity. Choice C reason: Exudative bronchitis is not empyema. It is a type of bronchitis that involves inflammation and excess mucus production in the bronchi, the airways that carry air to the lungs. Choice D reason: Infection localized in the lung is not empyema. It is pneumonia, which is an inflammation of the lung tissue, usually caused by a viral or bacterial infection that affects the air sacs or the interstitial tissue.