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: Anatomy
[{'content': 'Which of following is NOT a permanent mucosal fold in GIT? \nSelect and explain. \nA. Spiral valve of Heister, B. Gastric rugae, C. Plica semilunaris, D. Transverse rectal fold', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The mucosa and submucosa of the stomach are folded into the grossly visible gastric rugae. When the stomach is empty, the mucosa and submucosa contract into thick folds forming rugae. As the stomach distends, the rugae flatten.', 'role': 'assistant'}]