Answer:
The correct option is;
Prisoners traded for what they wanted
Explanation:
In the war camps, being that there where no privileged persons, everyone had to trade what they where given as rations for what they needed and as such trading became predominant in the camp as those who could afford to manage without taking some of the package contents from the Red Cross such as beef, coffee, biscuits and cheese can trade for other items with some making small fortunes in cigarettes (which became more or less the currency) and biscuits.