You are answering a USMLE-style medical question. Question: A 30-year-old male presents to the emergency department with a complaint of abdominal pain. The patient states he was at a barbecue around noon. Lunch was arranged as a buffet without refrigeration. Within 2 to 3 hours, he had abdominal pain with 3 episodes of watery diarrhea. On exam, vital signs are T 99.1, HR 103, BP 110/55, RR 14. Abdominal exam is significant for pain to deep palpation without any rebounding or guarding. There is no blood on fecal occult testing (FOBT). What is the most likely cause of this patient's presentation? Options: A) Salmonella enteritidis B) Listeria monocytogenes C) Staphylococcus aureus D) Vibrio cholerae Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.