• A → 1, B → 2, C → 3, D → 4

  • A → 2, B → 1, C → 3, D → 4

  • A → 1, B → 2, C → 4, D → 3

  • A → 4, B → 3, C → 2, D → 1


A → 1, B → 2, C → 3, D → 4