This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Stomach & Duodenum, Subject name: Surgery
Tell your diagnosis: 
Select and explain. 
A. Intestinal obstruction, B. Perforation peritonitis, C. Paralytic ileus, D. Chiladiti's syndrome
B: Perforation peritonitis
Answer: B: Perforation peritonitis 
Explanation: Ans. (b) Perforation peritonitis* Air under diaphragm on the right side indicates a hollow viscus perforation* The best imaging for hollow viscus perforation is X -ray abdomen erect* The minimum amount of air detected on erect X-ray: 1ML.* If patient cannot stand erect due to peritonitis: Left lateral decubitus X-ray is taken. This image will detect 5-10mL of air.* Chiladiti's Syndrome: Interposition of colonic shadow between the liver and diaphragm appears like perforation air under diaphragm.