Task: Question Understanding
Input (English): Question: Marvin went to the doctor and was given a vaccine containing a virus. When Marvin was surprised that the vaccine contained a virus, the doctor explained that viruses and other microorganisms (A) only cause sickness. (B) can have benefits to people. (C) are rarely useful to people. (D) should not be placed in the body.?
Output (English): doctor, vaccine, virus.