Which of the following is the correct order of increasing field strength of ligands to form coordination compounds ?

• A

  ${\mathrm{SCN}}^{-}<{\mathrm{F}}^{-}<{\mathrm{CN}}^{-}<{\mathrm{C}}_2{\mathrm{O}}_4^{2-}$

• B

  ${\mathrm{F}}^{-}<{\mathrm{SCN}}^{-}<{\mathrm{C}}_2{\mathrm{O}}_4^{2-}<{\mathrm{CN}}^{-}$

• C

  ${\mathrm{CN}}^{-}<{\mathrm{C}}_2{\mathrm{O}}_4^{2-}<{\mathrm{SCN}}^{-}<{\mathrm{F}}^{-}$

• D

  ${\mathrm{SCN}}^{-}<{\mathrm{F}}^{-}<{\mathrm{C}}_2{\mathrm{O}}_4^{2-}<{\mathrm{CN}}^{-}$