question: Q:A 42-year-old man presents with unremitting diarrhea that has lasted for 2 weeks. He describes his bowel movements as watery, non-bloody, foul-smelling, and greasy. He also has cramping abdominal pain associated with the diarrhea. He says that his symptoms started right after he returned from a father-son camping trip to the mountains. His son has similar symptoms. His vital signs include: pulse 78/min, respiratory rate 15/min, temperature 37.2°C (99.0°F), and blood pressure 120/70 mm Hg. A stool sample is obtained and microscopic analysis is significant for the findings shown in the image below. Which of the following pathogens is most likely responsible for this patient’s condition?? 
  {'A': 'Bacillus cereus', 'B': 'Campylobacter jejuni', 'C': 'Clostridium difficile', 'D': 'Giardia lamblia', 'E': 'Yersinia enterocolitica'},