Presumes to be service-connected, and therefore compensable through veterans' disability compensation, hepatitis C becoming manifest to a degree of ten percent or more after active-duty military service with respect to veterans who, during a period of such service: (1) received a transfusion of blood or blood products before December 31, 1992; (2) were exposed to blood on or through the skin or a mucous membrane; (3) underwent hemodyalisis; (4) experienced a needle-stick accident or medical event involving a needle, not due to the veteran's willful misconduct; (5) were diagnosed with or experienced unexplained liver disease or dysfunction; or (6) served in a health-care position or specialty under circumstances to be prescribed by the Secretary of Veterans Affairs.