What are the biggest advantages the U.S. has over the EU in terms of being an Optimum Currency Area? ...

[ 1 ]  C

[ 2 ]  The statement is true. Under floating rates, a rise in real domestic money demand causes income to fall and to an appreciation of the domestic currency. If the rise in real domestic money supply is permanent, it will lead eventually to a fall in the home price level.
Under a fixed exchange rate, the change in real money demand does not affect the economy at all. To prevent the home currency from appreciating, the central bank buys foreign reserves with domestic money until the real money supply rises by an amount equal to the rise in real money demand. This intervention has the effect of preventing any change in output or the price level.

[ 3 ]  EU countries should satisfy:
(1 ) Low inflation rate (no more than 1.5 percent above the average of the three EU member states with the lowest inflation).
(2 ) A stable exchange rate within the ERM.
(3 ) Public-sector deficit no higher than 3 percent of its GDP in general.
(4 ) A public debt below or approaching a reference level of 60 percent of its GDP.

I know this sounds cliche, but I was thinking the same thing for each of these. Thanks for confirming

I'm sure Thanks for your honesty