When a negative externality exists, the marginal social cost is always higher than the marginal private cost. So, the correct answer is option A the private marginal costs are less than social marginal costs.
<h3><u>What is a negative externality?</u></h3>
When the manufacturing process has a negative impact on unconnected third parties, this is referred to as a negative production externality. For instance, manufacturing facilities contribute to noise and air pollution throughout the production process.
<h3><u>What happens when a negative externality exists?</u></h3>
The marginal social cost and the marginal private cost are no longer equal when a market has negative production externalities. As a result, the supply curve (which indicates the marginal private cost) does not accurately reflect the marginal societal cost and the social cost is instead larger due to the externality's per-unit cost.
You can learn more about negative externality using the following link:
brainly.com/question/13901028
#SPJ4