Which of the following statements is true?

	a.	If the confidence interval estimate for the regression slope coefficient, based on the sample information, crosses over zero, the true population regression slope coefficient could be zero.
	b.	R-square will tend to be smaller than the adjusted R-squared values when insignificant independent variables are included in the model.
	c.	The y-intercept will usually be negative in a multiple regression model when the regression slope coefficients are predominately positive.
	d.	None of the above.