The Du Pont System shows which of the following series of relationships?

	a.	Net profit margin x total asset turnover = Return on investment.
	b.	Net profit margin x financial leverage = Return on equity.
	c.	Net profit margin x total asset turnover = Return on investment and Return on investment x financial leverage = Return on equity.
	d.	Net profit margin x total asset turnover = Return on equity and Return on equity x financial leverage = Return on investment.