Ans. is 'a' i.e., Lower lobe involvement Pneumococcal pneumonias have predilection to involve the right lower lobe, whereas Klebsiella usually affects one of the upper lobes. Features Pneumoccoccal Pneumonia Klebsiella Pneumonia Consolidation pattern Lobar consolidation with positive air bronchogram sign Lobar Consolidation with positive air bronchogram sign Lobe predilection Predilection to involve Lower Lobe (Any lobe may be involved) Usually unilobar (usually do not expand involved lobe) Commonly involves posterior segment of the rightupper lobe (Bulging fissure sign Abscess Abscess formation uncommon Abscess formation rare but more common than streph Pleural effusion Pleural effusion uncommon Pleural effusion common (empyema) Cavitation Pleural effusion uncommon Cavitation is common