What must be included in a secondary suite according to safety regulations?

In the context of safety regulations for secondary suites, the inclusion of interconnected smoke and carbon monoxide alarms is crucial. These alarms provide an essential safety feature by ensuring that if one alarm detects smoke or carbon monoxide, all interconnected alarms will sound, alerting residents throughout the suite and, if applicable, the primary dwelling. This interconnectedness significantly increases the likelihood of residents being alerted to potential dangers, thereby enhancing their safety.

The other choices—such as having an attached garage, a shared heating and ventilation system, and direct access to common areas—are not typically mandated under safety regulations for secondary suites. While they may be relevant considerations for the overall design or functionality of a secondary suite, they do not enhance fire or carbon monoxide safety in the same way that interconnected alarms do. Therefore, the correct answer focuses on the critical aspect of ensuring adequate safety measures are in place for residents of secondary suites.