Q. Which of the following is correct about hepatitis

(a) hepatitis B and C are spread by parenteral route and hepatitis A via fecal oral route
(b) Incubation period of hepatitis B is of 30 to 180 days and hepatitis A is of 15 to 45 days
(c) Hepatitis B is caused by DNA virus and others are caused by RNA virus
(d) all of the above