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 patient presents with a lower gastrointestinal bleed. Sigmoidoscopy shows ulcers in the sigmoid. Biopsy from this area shows flask-shaped ulcers. Which of the following is the most appropriate treatment - 
Select and explain. 
A. Intravenous ceftriaxone, B. Intravenous metronidazole, C. Intravenous steroids and sulphasalazine, D. Hydrocortisone enemas
B: Intravenous metronidazole
Answer: B: Intravenous metronidazole 
Explanation: None