Which one of the following statements is incorrect in fe4 efficiency thrice a ligand and satisfied only the secondary valency of ferrous iron?
1) The efficiency of fe4 is thrice that of a ligand
2) The efficiency of fe4 satisfies only the secondary valency of ferrous iron
3) The efficiency of fe4 is satisfied by both primary and secondary valency of ferrous iron
4) The efficiency of fe4 is satisfied by only the primary valency of ferrous iron