fatigue, fever, nausea, and dark urine

A company held an elaborate holiday dinner party for
its 42 employees. Within three to four weeks, many of
the banquet attendees complained of experiencing
fatigue, fever, nausea, and dark urine, and were observed to be jaundiced.
The group exhibited no
bacterial infections in common. The employees who
became ill had all eaten raw oysters at the party. The
company doctor assayed a sample of the employees'
blood for anti-hepatitis B antibodies, but all samples
were negative for anti-HBsAg IgM. The causative
agent consistent with this history is most likely:

A. hepatitis A virus
B. hepatitis B virus
C. hepatitis C virus
D. hepatitis D virus
E. hepatitis E virus