Final answer:
The village elders were addressing the economic issue known as the Tragedy of the Commons, which is the depletion of a shared resource by individuals acting on self-interest. Their solution was social exclusion, a penalty for those who violate community rules.
Step-by-step explanation:
The economic problem the village elders were trying to prevent is B) Tragedy of the Commons. This scenario illustrates when individuals, acting according to their self-interest, overuse a common resource, leading to its depletion. The tragedy of the commons embodies the difficulty of shared resources management, where individual needs and collective welfare can be at odds.
The solution of the village elders to outcast those who committed the breach of trust for fishing in the pond when it was forbidden is an example of A) Social exclusion. This measure serves as a non-economic sanction, where the community enforces rules by excluding members who violate them, to protect common resources and ensure sustainability.