Which story is most likely an example of an allegory?
 A. Two men, struggling with crippling debt, rob a bank and are forced
 to take several hostages after the robbery goes horribly wrong.
 B. A single mother goes to school at night and eventually gets a
 college degree so she can provide a better life for her children.
 C. A lonely angel falls from the sky and learns to fly again only after
 he performs miracles that help to keep a poor couple's farm
 afloat.
 D. A small dog, accidentally lost during a family move, struggles to
 overcome several obstacles as he finds his way back home.