Final answer:
The single most important source of HIV and HBV in the workplace is contaminated needles and sharps (Option A).
Step-by-step explanation:
The primary source of HIV and HBV in the workplace is contaminated needles and sharps. Health-care settings can minimize transmission through proper use of PPE, safe needle practices, hand hygiene, and immediate post-exposure action.
Health care environments pose a risk where professionals might encounter infected body fluids, especially blood, through sharp-related injuries. HIV and Hepatitis B Virus (HBV) are not transmitted through casual contact, airborne particles, or a contaminated water supply. Infection occurs through direct exposure to infected bodily fluids via activities such as needle sticks, IV drug use, sexual transmission, and transfusions.
To reduce the transmission of HBV in health-care settings, stringent precautionary measures like the use of personal protective equipment (PPE), safe handling and disposal of needles and sharps, regular hand hygiene, and prompt post-exposure interventions are essential. Though vaccines provide significant protection, adherence to proper protocols and practices is vital to minimize risks.
Thus, the correct option is A.