This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
Which one of the following groups of people may be at increased risk for HIV infection? 
Select and explain. 
A. Members of a household in which there is a person who is HIV-positive, B. Receptionists at a hospital, C. Factory workers whose coworkers are HIV-positive, D. Foreign service employees who are hospitalized in Zaire for bleeding ulcers
D: Foreign service employees who are hospitalized in Zaire for bleeding ulcers
Answer: D: Foreign service employees who are hospitalized in Zaire for bleeding ulcers 
Explanation: Many believe that casual contact with patients who are HIV-positive increases the risk of acquiring the disease. This is not the case. It is also clear that homosexual females have a low rate of HIV acquisition. Because a substantial portion of the blood supply in Central African countries is HIV-infected, hospitalization is risky particularly if transfusion is necessary.