Suppose the labour force and (physical) capital stock are growing at a rate of 2.5% and 3% respectively, and the labour share of income is 60%. In addition, the total factor productivity is presently constant. We would like to have a very long-run growth rate of real GDP of 3% that will be obtained by changing the growth rate of ONLY one of the following three - the labour force; the capital stock; or total factor productivity. Workers would find all three of these choices equally desirable. Explain your answer with the use of mathematics, economics, and words. (4 points) Note: All the growth rates are annual rates.