Final answer:
Gilberto's landscaping activities would create a positive externality, which benefits others in the neighborhood without incurring costs to them.
Step-by-step explanation:
The question at hand deals with the concept of externalities, which are outcomes (positive or negative) experienced by third parties who are not directly involved in an activity or transaction. In Gilberto's case, the landscaping and beautification of his yard would create a positive externality, as it enhances the aesthetic appeal of the neighborhood without the neighbors incurring any cost. This positive impact extends beyond Gilberto's property and benefits others in the vicinity. Option b is correct .
An example of a negative externality could be pollution from a factory, where the costs of pollution are suffered by individuals who are neither the producers nor consumers of the factory's products. In this case, the landscaping done by Gilberto beautifies the neighborhood, making it more visually appealing to everyone in the community. The aesthetic improvement of the neighborhood is a positive externality that generates benefits for others.