A 25-year-old man presents with a 2-week history of bloody diarrhoea, urgency and tenesmus. Stool cultures are negative. Flexible sigmoidoscopy shows continuous mucosal inflammation extending from the rectum. What is the most likely diagnosis?AUlcerative colitisBCrohn’s diseaseCInfective colitisDIrritable bowel syndromeEDiverticulitisCheck my answer