Q6. You want to fit a cubic spline to a large dataset and need to determine the number of knots to use. Below is a chart of four statistics from this model valued for various numbers of knots: 2.0 26 0 95 0.5 CO 2 Number of Knots x Determine which set of statistics below best describes each line and why? A. W is Test MSE; X is Variance; Y is Squared Bias; Z is Train MSE B. W is Variance; X is Squared Bias; Y is Test MSE; Z is Train MSE C. W is Train MSE; X is Test MSE; Y is Variance; Z is Squared Bias