question: Q:A 45-year-old man presents to the emergency department with abdominal distension. The patient states he has had gradually worsening abdominal distension with undulating pain, nausea, and vomiting for the past several months. The patient does not see a physician typically and has no known past medical history. He works as a farmer and interacts with livestock and also breeds dogs. His temperature is 98.7°F (37.1°C), blood pressure is 159/90 mmHg, pulse is 88/min, respirations are 15/min, and oxygen saturation is 99% on room air. Physical exam is notable for mild abdominal distension and discomfort to palpation of the upper abdominal quadrants. Laboratory values are ordered and are notable for a mild eosinophilia. A CT scan of the abdomen demonstrates multiple small eggshell calcifications within the right lobe of the liver. Which of the following is the most likely etiology of this patients symptoms?? 
  {'A': 'Echinococcus granulosus', 'B': 'Enterobius vermicularis', 'C': 'Necator americanus', 'D': 'Taenia saginata', 'E': 'Taenia solium'},