What Is the CORRECT Order of Steps in Vesicle Fusion

What is the CORRECT order of steps in vesicle fusion to a cell?

A) outer leaflet lipid mixing, content release, inner leaflet lipid mixing
B) outer leaflet lipid mixing, inner leaflet lipid mixing, content release
C) inner leaflet lipid mixing, content release, outer leaflet lipid mixing
D) inner-leaflet lipid mixing, outer leaflet lipid mixing, content release
E) content release, inner leaflet lipid mixing, outer leaflet lipid mixing