QUESTION 14 (a) Explain the efficiency-equity trade-off of labour income taxes using as reference the differences between proportional and progressive linear income tax schedules. Support your explanation with a graphical illustration. (4 points) (b) Explain how nonlinear income tax structures may be able to increase the amount of redistribution without increasing the deadweight loss associated with the tax. Support your explanation with a graphical illustration. (3 points) (c) "If there are groups in the population that differ in their labour supply elasticity, they should be taxed at different rates". Justify this in terms of the theory of optimal taxation, and discuss its implications for the joint taxation of working spouses. (3 points) _________________________________________