Answer:
(C). Firms engaged in barter run the risk of having to accept goods they do not want or cannot use.
Explanation:
Countertrade is a trade system in which goods and services are exchanged for other goods and services.
Barter is a type of countertrade where money isn't involved. Only goods and services are exchanged between participating parties.
A disadvantage of barter is that, in the absence of required goods, a firm may have to accept the goods the other firm is offering even though it doesn't need or cannot use those goods at that point in time. The firm could resell the goods later.