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: Surgery
Egg shell pattern on X-ray abdomen may be seen in: 
Select and explain. 
A. Testicular torsion, B. Hydrocele, C. Meconium ileus, D. All of the above
C: Meconium ileus
Answer: C: Meconium ileus 
Explanation: In patients with complicated meconium ileus, intraperitoneal calcifications form, producing an eggshell pattern on plain abdominal radiograph. Ref: Schwaz's principle of surgery 9th edition, chapter 39.