In country A, it takes 10 labor hours to produce cloth and 20 labor hours to produce grain. In country B, it takes 20 labor hours to produce cloth and 10 labor hours to produce grain. Which country should produce grain? 

      A. No country should produce grain.       B.  A. 

  C. Both A and B should produce grain.     D. B. 

이문제인데 takes 10 labor hours to produce  라는 부분은 생산하는데 10시간이 걸린다는건가요?? 낮을수록 효율이 좋은거 맞죠?? 근데 왜 답은 2번 B국가가 곡물을 생산해야한다고 나오는데 이해가 안되요 ㅠㅠ