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: Radiology
If the right cardiac silhouette is obliterated, it means the pathology involves – 
Select and explain. 
A. Right lower lobe, B. Right atrium, C. Right middle lobe, D. Right ventricle
C: Right middle lobe
Answer: C: Right middle lobe 
Explanation: Right middle lobe lesion causes obliteration of the right cardiac border (right cardiac silhouette).