You are answering a USMLE-style medical question. Question: Public health researchers are reviewing data from an outbreak of hepatitis A that was traced to contaminated produce from a popular restaurant. A case series investigation with prospective and retrospective follow-up found that 500 individuals dined at the restaurant during the week of study. The incidence of hepatitis A infection was found to be 25%, and the total number of deaths recorded among the incident cases was 5 individuals. What was the case-fatality rate for the hepatitis A outbreak? Options: A) 4% B) 10% C) 20% D) 25% Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.