This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
Undulant fever is caused by - 
Select and explain. 
A. Baonella, B. Brucella melitensis, C. Bordetella, D. Borelia recurrentis
B: Brucella melitensis
Answer: B: Brucella melitensis 
Explanation: Ans. is 'b' i.e., Brucella melitensis . Acute brucellosis also known as undulant fever is mostly due to Br. melitensis.