PLEASE HELP WILL GIVE BRAINLIEST I have a variety of questions for my test just go to my account and hit questions and answer the ones that haven't been answered or the answers aren't good pllsss I will give you extra points on another one if necessary I jus need to pass!! Thank you so much!

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