What jurisdiction does Ontario have if an agreement under subsection (2) is in effect?

The correct answer highlights that Ontario maintains jurisdiction for the enforcement of the Act in the municipality when an agreement is in effect. This underscores the role of provincial oversight in ensuring that the local municipalities adhere to the regulations and standards set out in the legislation. The enforcement aspect is crucial because it ensures compliance with the building code, maintaining the safety, accessibility, and overall quality of building practices within the municipality.

In scenarios where agreements establish certain responsibilities or delegations, the province often retains a degree of control to make sure that regulations are applied uniformly and effectively throughout all municipalities in Ontario. This helps to ensure that despite any local agreements, the overall standards outlined by the provincial building code are upheld, protecting public interest and safety.

Other options may involve various areas of jurisdiction; however, they do not focus on the enforcement aspect specifically tied to the Act, which is central to understanding the province's role in managing municipal adherence to building regulations.