3. (a) What is regularization in the context of machine learning? (b) Define and briefly discuss ridge regression. (c) What is the LASSO in regression analysis? What is the main difference between the ridge regression and LASSO?[10 marks] (d) What is "subset selection"? Discuss the two stepwise selection methods in the context of linear regression. (e) What is meant by a maximal margin classifier? Name one example of maximal margin classifiers. (f) What is the "kernel trick" in machine learning?