Among $\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+},\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-},\left[\mathrm{Fe}(\mathrm{Cl})_{6}\right]^{3-}$ species, the hybridisation state of the $\mathrm{Fe}$ atom are, respectively.

• A

  $d^{2} s p^{3}, d^{2} s p^{3}, s p^{3} d^{2}$
• B

  $s p^{3} d^{2}, d^{2} s p^{3}, d^{2} s p^{3}$
• Correct answer
  C

  $s p^{3} d^{2}, d^{2} s p^{3}, s p^{3} d^{2}$
• D

  None of the above

Hence, the correct answer is option: 'C'.