How Many Electrons Can an Allyl Ligand Donate?
A) In $\eta$

How many electrons can an allyl ligand donate?

A) In $\eta$ ¹ bonding mode two electrons with single negative charge, in $\eta$ ³ mode three electrons with single negative charge.
B) In $\eta$ ¹ bonding mode two electrons with single negative charge, in $\eta$ ³ mode four electrons with single negative charge.
C) In $\eta$ ¹ bonding mode one electron with single negative charge, in $\eta$ ³ mode three electrons with single negative charge.