Suppose that an economy has a labour force of 36 (Lt = L = 36). Population growth is equal to zero (n = 0), so L = 36 in all periods. Suppose also that this economy has a savings rate given by s (s = 10%), and a depreciation rate of 10% (δ = 0.1). The economy's Total Factor Productivity (TFP), given by "A" is equal to 20. Finally, this economy has a production function given by: (Yt, Kt) = A * Kt0.5 * Lt0.5. What is the equation for capital per capita next period (kt+1) as a function of capital per capita this period (kt)?

a. kt+1 = 0.1kt + 18
b. kt+1 = 0.9kt + 2
c. kt+1 = 0.2kt + 16
d. kt+1 = 0.8kt + 4