Final answer:
The Coase Theorem would not apply in situation d. Many firms are working together to eliminate pollution because it would result in high transaction costs.
Step-by-step explanation:
The correct answer is d. Many firms are working together to eliminate pollution.
The Coase Theorem states that if transaction costs are low and property rights are well-defined, then parties will negotiate and internalize externalities in order to reach an efficient outcome. However, if transaction costs are too high, it becomes difficult for parties to negotiate and reach an agreement.
In option d, many firms working together to eliminate pollution may lead to high transaction costs. Coordinating the efforts of multiple firms can be challenging and time-consuming, resulting in higher costs associated with negotiation.