NADPH Is a Two Electron Donor

NADPH is a two electron donor. Heme can only accept one electron. How is this accommodated in the microsomal electron transport chain?

A) NADPH binds heme, leaves, and rebinds heme
B) NADPH donates on electron to an iron-sulfur protein
C) NADPH gives electrons to a flavoprotein with two flavin groups
D) NADPH gives electrons to two flavoproteins with one flavin group each
E) NADPH transfers only one electron