Which of the following is NOT true about in multiple regression?

	A.	can be artificially increased by adding explanatory variables to the model, even if they are not related to the response variable.
	B.	can be equal to 1.
	C.	adjusts for the sample size and the number of explanatory variables in the fitted model.
	D.	describes the proportion of the variation in the response variable that is explained by the fitted model