Which reason below is NOT a reason why Germany gave up in WWI: shortage of supply
shortage of food
The French kidnapped German families in Berlin.
the arrival of the American's made the German's realize they had no chance

One drawback of voluntary trade is that it a. requires two groups to use a common language b. can make one group dependent upon another for necessary goods c. doesn't occur unless there is a shortage of goods for at least one group d. forces groups to rely on themselves to produce all the goods they need