What key phrases are included in the definitions of the objectives?

The choice that highlights key phrases from the definitions of the objectives is correct because it specifically relates to the language used in the Ontario Building Code when discussing risk management and safety. The phrases 'limit the probability' and 'unacceptable risk' focus on the assessment and mitigation of possible hazards associated with building construction and occupancy. This aligns with the objective of ensuring safety for occupants and the structural integrity of buildings.

In the context of the building code, these phrases emphasize the proactive approach to minimizing risks that could lead to injuries or failures. By setting limits on the probability of risks, the building code aims to establish a baseline for safety and performance standards that all buildings should meet to protect public welfare.

Other options, while they may represent important goals in construction and building design, do not encapsulate the fundamental focus on risk assessment and safety that is pivotal in the context of building regulations. For instance, ensuring structural integrity addresses safety but does not touch on the deeper risk management language found in the definitions. Similarly, maximizing energy efficiency or reducing construction time and costs, while significant for sustainability and economics, do not address the critical safety considerations reflected in the risk-oriented phrases.