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
Which of the following condition is associated with the presence of Kerley B lines on chest X ray? 
Select and explain. 
A. COPD, B. Interstitial oedema, C. Pulmonary aery hypeension, D. Pulmonary plethora
B: Interstitial oedema
Answer: B: Interstitial oedema 
Explanation: Kerley B lines indicates thickening of interlobular septa. It occurs in interstitial oedema. They are horizontal, 1-2 cm in length, touch the pleural surface and is best seen laterally in the costophrenic angles. This appearance results from the regular organisation of pulmonary lobules at the lung bases. Interstitial edema is manifested on chest X Ray by: Kerly A or B lines Thickening of fissures Peribronchial cuffing Poor definition of pulmonary office or perihilar haze On CT these findings corresponds to: Smooth interlobular septal thickening Subpleural edema Thickening of the peribronchovascular interstitium Ground glass opacity Ref: Thoracic Imaging: Pulmonary and Cardiovascular Radiology