This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
[{'content': 'Pseudomembranous colitis, all are true except: \nSelect and explain. \nA. Toxin A is responsible for clinical manifestation, B. Toxin B is responsible for clinical manifestation, C. Blood in stools is a common feature, D. Summit lesions is early histopathological finding', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. is \'c\' i.e., Blood in stools is a common feature.Ref: Topley\'s, 10th/e, p. 1120-1121"Frank blood in stool is not common.")ABOUT OTHER OPTIONSOption (a) and option (b)* Toxin A and B both are responsible for clinical manifestation."Once C. difficile is established in the bowel, disease is a consequence of the production of two large protein toxins, Toxin A and B."* Toxin A has both histotoxic and enterotoxic activity and is of major importance in causation of tissue damage and luminal fluid accumulation.* Toxin B may independently cause tissue damage.Option (d)"In the earliest stage of disease \'summit-lesions\', tiny superficial intercryptal erosions, may be found."', 'role': 'assistant'}]