A least squares regression line

A) can be used to predict a value of y if the corresponding x value is given.
B) implies a cause-and-effect relationship between x and y.
C) can only be determined if a good linear relationship exists between x and y.
D) ensures that the predictions of y outside the range of the values of x are valid.

A least squares regression line can be used to predict a value of y if the corresponding x value is given. It is a way of describing the relationship between two variables in a linear fashion and can be used for making predictions within the range of observed x values. However, it does not imply a cause-and-effect relationship between x and y, and predictions outside the range of observed x values may not be as reliable.