Write brief notes on ANY TWO of the following. Include diagrams, exam- ples and illustrations from the current environment in New Zealand where appropriate. (a) [5 marks] Using experimental methods to design a good health insur- ance system. (b) [5 marks] Methods of achieving progressive income taxation. (c) [5 marks] Whether the first welfare theorem implies that all competi- tive equilibria are efficient. (d) [5 marks] Internalising externalities. (e) [5 marks] The Working for Families tax credit program.