I wish I knew to whom I should give credit for this story. Dad29 credits Chesterton for the analysis that reminded me of it.
The teacher said that all Literature is built on five themes; money, sex, religion, family and mystery. She offered a prize to the student who could most concisely use all five in a single story.
The winning entry read in full; "Oh, My God," cried the Banker's Daughter. "I'm pregnant! I wonder whose it is."