Which of the Following Would Be Considered a Serious Game

Which of the following would be considered a serious game?

A) on a computer, use virtual flashcards that teach about Nazi Germany, Battle of the Bulge, and the  Holocaust
B) on a computer, design an amusement park and learn about money, accounting, and prediction with statistics
C) with a game console, play a first-person shooter game where the goal is to kill the enemy
D) out on the playground, play dodge ball