<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 67-year-old man presents to the physician with profuse watery diarrhea along with fever and crampy abdominal pain. He has been taking an antibiotic course of cefixime for about a week to treat a respiratory tract infection. At the doctors office, his pulse is 112min, the blood pressure is 10066 mm Hg, the respirations are 22min, and the temperature is 38.9C 102.0F. His oral mucosa appears dry and his abdomen is soft with vague diffuse tenderness. A digital rectal examination is normal. Laboratory studies show:Hemoglobin 11.1 gdLHematocrit 33Total leucocyte count 16,000mm3Serum lactate 0.9 mmolLSerum creatinine 1.1 mgdLWhat is most likely to confirm the diagnosis?? A: Identification of C. difficile toxin in stool, B: Stool culture, C: Colonoscopy, D: Abdominal X-ray, E: CT scan of the abdomen,  <response>: This is a patient with acute diarrhea likely caused by antibiotic-associated Clostridium difficile infection. The key features are watery diarrhea, fever, abdominal pain, and recent antibiotic use. The question asks for the test most likely to confirm the diagnosis. Stool testing for C. difficile toxin is the most appropriate first step to confirm C. difficile infection. Stool culture can detect C. difficile but toxin testing is more sensitive. Colonoscopy and imaging are not first line tests to diagnose C. difficile infection.A: Identification of C. difficile toxin in stool 