question: Q:A 32-year-old man is brought to the physician by his wife for a 3-day history of fever, headaches, and myalgias. He returned from a camping trip in Oklahoma 10 days ago. He works as a computer salesman. His temperature is 38.1°C (100.6°F). Neurologic examination shows a sustained clonus of the right ankle following sudden passive dorsiflexion. He is disoriented to place and time but recognizes his wife. Laboratory studies show a leukocyte count of 1,700/mm3 and a platelet count of 46,000/mm3. A peripheral blood smear shows monocytes with intracytoplasmic morulae. Which of the following is the most likely causal organism?? 
  {'A': 'Coxiella burnetii', 'B': 'Rickettsia rickettsii', 'C': 'Anaplasma phagocytophilum', 'D': 'Ehrlichia chaffeensis', 'E': 'Borrelia burgdorferi'},