The addition of dilute $NaOH$ to $Cr^{3+}$ salt solution will give:

• A
  a solution of $[Cr(OH)_{4}]^{-}$
• B
  precipitate of $Cr_{2}O_{3} \cdot nH_{2}O$
• C
  precipitate of $[Cr(OH)_{6}]^{3-}$
• D
  precipitate of $Cr(OH)_{3}$