4. The intertemporal budget constraint with three periods: Consider an economy that exists for three periods: period 1, period 2,and period 3.In each period, the government must satisfy the budget constraint B,,; = (1 + i)B, + G, T,. (a) Write this budget constraint for each period. (b) What must be true about B,? (c) Using the result from part (b), solve the period 3 budget constraint for B;, and substitute this back into the period 2 budget constraint. (d) Solve this new version of the period 2 budget constraint for B,, and substitute the result back into the period 1 budget constraint. (e) At this point, you should have the intertemporal budget constraint for the three-period economy. Interpret this equation