Which Statement Is True

Which statement is true?

A) Comparative advantage means that total world output will be greatest when each good is produced by the nation that has the highest domestic opportunity cost.
B) Comparative advantage means that total world output will decline when each good is produced by the nation with the lowest domestic opportunity cost.
C) Specialization is complete among nations when opportunity costs rise as any given nation produces more of a particular product.
D) Specialization is less than complete among nations when opportunity costs rise as any given nation produces more of a particular product.