This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
[{'content': 'Organism most likely to cause "fever of unknown origin" in a farmer who raises goats \nSelect and explain. \nA. Brucella melitensis, B. Clostridium novyi, C. Histoplasma capsulatum, D. Mycobacterium tuberculosis', 'role': 'user'}, {'content': "Answer: A \nExplanation: Human brucellosis is acquired from animals, directly or indirectly. Goats, sheep, cattle, buffalos, and swine are common sources. Most human infections in various pas of India are due to B.melitensis acquired from goats and sheep. Ref: Textbook of microbiology; Ananthanarayana and paniker's; 10th edition; Pg: 348", 'role': 'assistant'}]