please help due tmm.

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

During industrialization which led to an exploration of new economic theories

Hay's policy concerning trading rights in china was the: a. protectionist policy b. open-door policy c. square deal