This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
A person's X-ray chest showing homogenous opacity on right side with shifting of mediastinum on opposite side. Most probable diagnosis is/are: 
Select and explain. 
A. Collapse, B. Pleural effusion, C. Pneumothorax, D. Consolidation
B: Pleural effusion
Answer: B: Pleural effusion 
Explanation: Answer- (B) Pleural effusionPneumonectomy chest (Early sip: within 24 hr): Paial filling of thorax, ipsilateral mediastinal shift & diaphragmatic elevation.Homogenous opacityShift of mediastinum to the opposite sideConcave upper border (Ellis's curve)