1. Let us imagine the world where we have only one currency. In this world, people travel freely, and jobs are available in many different cities. Let us further imagine that an economic shock hits a part of this world, but many countries refused to help the affected country in terms of financial aid. Would you consider such a world 'optimal' (in terms of 'OCA')? Why? Why not? (Please comment on all criteria of the OCA.) In this world, can each country maintain independent monetary policy? Why? Why not?