The correct answer is B - abdominal pain at least once weekly. The Rome Criteria were developed by consensus to diagnose functional gastrointestinal disorders. The criteria for Irritable Bowel Syndrome include recurrent abdominal pain, on average, at least 1 day/week in the last 3 months, associated with two or more of the following criteria: related to defecation, associated with a change in frequency in stool, associated with a change in form/appearance of stool. Symptom onset must be 6 months before diagnosis. Increased (NOT reduced) visceral hypersensitivity is a proposed pathophysiologic mechanism of IBS, but pathophysiology is not part of the Rome criteria. Fermentable oligo-, di-, and monosaccharides (FODMAPS) are short chain carbohydrates that may be poorly absorbed by the intestine, and fermentable by enteric bacteria, producing H2 and methane, leading to bloating and abdominal pain. Several RCTs show reduction (NOT worsening) in IBS symptoms with a low FODMAP diet. However, this is not part of the Rome Criteria. Abdominal pain with weight loss would signify an “alarm” symptom that may suggest a more serious underlying GI condition.

Publication reference : Lacy BE et al. Bowel Disorders - Part of Rome IV - Functional GI Disorders: Disorders of Gut-Brain Interaction. Gastroenterology. 2016;150(6):1393-1407.
Reference URL: https://doi.org/10.1053/j.gastro.2016.02.031
Publication reference : Crone CC, Lackamp JM, Alkis AR. Gastrointestinal Disorders. In: Levenson JL, ed. The American Psychiatric Association Textbook of Psychosomatic Medicine and Consultation-Liaison Psychiatry. Third ed. Washington DC: American Psychiatric Association Publishing; 2019:527-569.