Which of the Following Statements Is True

Which of the following statements is true?

A) If a country can produce a good at a lower cost than others, then it has a comparative advantage in producing that good.
B) If a country can produce a good at a higher opportunity cost than others, then it has a comparative advantage in producing that good.
C) If a country has an absolute advantage in producing all the goods, it can still engage in mutually beneficial trade with other countries.
D) If a country does not have an absolute advantage in producing any good, then it cannot have a comparative advantage in producing any good.