Which economists system ( capitalism, socialism, communism) is the most powerful?

Neither one is the most powerful for they all powerful in their own right. But communism fell after the wall of Berlin was torn down in the late 80's, so that brought tremendous damage to the system many refer to as communism. Though it would not be suprising of it still exist in other countries.

The U.S is mostly a capitalist economy system. Though we do have many charcteristics of a socialist economy.

In my opinion choice a would be the correct one