Which of the following is the causative agent of Malta fever?

In man Malta fever or brucellosis is caused by 4 species such as B abous, B melitensis, B suis, and B canis. In humans infection occurs with the ingestion of infected raw milk products, exposure to infected animals and aerosolization of the organism. Brucellosis is characterized by the presence of cyclical fever that stas two to three weeks post exposure. Other associated symptoms includes night sweats, headaches, backache and generalized malaise. Chronic brucellosis can lead to ahritis, dementia and death. Ref: Risk Infections and Possibilities for Biomedical Terrorism By Philip H. Elzer, page 11.