] >
  1. AB → C
    C → B
  2. Yes, on primary key AB. No, on primary key AC.
  3. No. For primary key AB, because B depends on C. For primary key AC, because even 2NF doesn’t hold.
  4. No. Missing records:
    +---+---+---+ 
    | A | B | C | 
    +---+---+---+ 
    | 3 | 1 | 3 | 
    +---+---+---+ 
    | 3 | 2 | 2 | 
    +---+---+---+ 

  5. No. Missing records:
    +---+---+---+ 
    | A | B | C | 
    +---+---+---+ 
    | 1 | 1 | 2 | 
    +---+---+---+ 
    | 2 | 1 | 2 | 
    +---+---+---+ 
    | 3 | 1 | 1 | 
    +---+---+---+