What is the effective date of S.O. 2006 c. 19, Schedule O, section 1?

The effective date of S.O. 2006 c. 19, Schedule O, section 1 is June 22, 2006, which is reflected in the choice selected. This date is significant as it marks when the legislative provisions outlined in this section officially came into effect and began to govern relevant building practices and regulations in Ontario. Understanding the effective date is crucial for professionals in the building and construction industry, as it informs them about the timeline of compliance and enforcement for various regulations that affect the design, safety, and execution of building projects.

The other dates listed are either prior to the enactment of the legislation or postdates that do not align with the specified effective date of June 22, 2006, which is why they do not represent the correct answer in the context of the Ontario Building Code.