If nation A produce one unit of commodity X needs 3 labor, produce one unit of commodity Y is 3 labor, while nation B can produce one unit of X needs 3 labor, produce one unit of Y needs 1 labor, (and labor is the only input):
A: nation A has a comparative disadvantage in commodity X
B: nation B has a comparative disadvantage in commodity Y
C: nation A has a comparative advantage in commodity X
D: nation A has a comparative advantage in neither commodity