Exam CIPP-C topic 1 question 41 discussion

A federally regulated company based in Ontario has customers in Ontario, Quebec, New Brunswick, Alberta and British Columbia. Unfortunately, a third-party vendor that provides marketing support to the company experiences a privacy breach which impacts the personal information of all its customers across the provinces where it operates.
The Privacy Officer determines that the breach causes a real risk of significant harm to their customers and is tasked with reporting the breach to the relevant regulators.
With which provincial privacy regulators does the company have to file a report?