In Ontario the mask mandate was formulated under theAReopening Ontario ActBSaving Ontario ActCRestructuring Ontario ActDStrengthening Ontario Act

The correct answer is A. Reopening Ontario Act.

The Reopening Ontario Act was introduced to provide a framework for the gradual reopening of the province's economy while ensuring public health and safety during the COVID-19 pandemic. This act empowered the government to implement public health measures, including mask mandates, to protect communities.

The other options, such as the Saving Ontario Act, Restructuring Ontario Act, and Strengthening Ontario Act, do not pertain specifically to the COVID-19 measures or the implementation of the mask mandate. Thus, the Reopening Ontario Act is the appropriate choice regarding the formation of the mask mandate in Ontario.