Answer:
Subsidize Montgomery for every three-eyed fish they find in the pond.
Step-by-step explanation:
From the question we are informed about Montgomery who owns a nuclear power plant in the town of Springfield. His power plant dumps substantial quantities of radioactive waste into the local pond, which has given rise to a mutant guppy fish population with three eyes.The town decides to have Montgomery do something about the externality. In this case the method that would NOT result in Montgomery accounting for the social cost of running the power plant is Subsidize Montgomery for every three-eyed fish they find in the pond. Social cost can be regarded as addition of private costs that comes from a transaction as well as costs that is been imposed on the consumers as a result of exposure to transaction that did not compensated or charged for. It is addition of both private and external costs. Therefore, if there is subsidy for three-eyed fish will prevent him from social cost