In the nitrogen fixation process,which step of the electron transfer process requires ATP hydrolysis?

A)transfer of electron from ferredoxin to the 4Fe-4S complex
B)transfer of electron from 4Fe-4S complex to the P cluster
C)transfer of electron from P cluster to iron-molybdenum cofactor (FeMo-co)
D)transfer of electron from FeMo-co to nitrogen
E)none of the above