How is double marginalization affected by profit margin

Question

Assignment:

How is double marginalization affected by the profit margin of the retailer (p 2 w) relative to the profit margin of the whole supply chain (p₂ - c)? Is its effect greatest when most of the profit margin sits with the retailer or with the supplier?

Your answer must be typed, double-spaced, Times New Roman font (size 12), one-inch margins on all sides, APA format and also include references.