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: Medicine
A young girl presents with abdominal pain and a recent change in bowel habit, with passage of mucus in stool. There is no associated blood in stool and symptoms are increased with stress. The most likely diagnosis is - 
Select and explain. 
A. Irritable bowel syndrome, B. Ulcerative colitis, C. Crohn's disease, D. Amebiasis
A: Irritable bowel syndrome
Answer: A: Irritable bowel syndrome 
Explanation: None