5. When the real interest rate is lower than the population gowth rate and the mandated social security savings are higher than what consumers would have saved on their own [in the absence of a social security system): {a} both the payasyougo and the fully funded system raise welfare. (1)] the payasyeu go system does not raise welfare, but the fully lnded system does. (e) neither the payasyeuge, nor the fully funded system raise welfare. {d} the pay-aseypu go system raises welfare, but the fully funded system does not. 5. Wliat is the optimal decision rule for a rm in choosing investment? {3) MPff+5=r (sag: (c) MPEMr=w'+5 (u) MP' = MP}, a 7, For a given exogenous increase in G, the equilibrium effect on real output in the res] intertemporal is smaller, (a) the smaller the response of labour supply to changes in lifetime wealth, and the smaller the intertemporal substitution eEect of the real interest rate on labour supply. (b) the larger the response of labour supply to changes in lifetime wealth, and the lower the sensitivity of the production function to changes in labour, (c) the lower the sensitivity of current consumption to changes in the real interest rate, and the steeper the output supply curve. (d) the larger the shift in the output supply curve, and the atter the output supply curve