Mrs. Brown is a lawyer, specialized in common-law and she
wants to create a company in order to operate her business
activities in all provinces and territories of Canada.
A) Indicate to Mrs. Brown which is the legal regime under
which she can incorporate her company: the federal or the
provincial regime? (5 points)

The basic difference between federal and provincial law is that federal law or the federal government enacts laws and legislation for all the state of the country while provincial laws are those laws that are for the specific province or state. Furthermore, the Federal government has the authority to enact criminal laws and enactments while the provincial law has got no such authority.
The Canadian Federal Government is solely responsible for making laws and legislation that covers and impacts the entire country while the provincial government has the authority to make enactments which directly impacts and concerns their territory. The federal laws concern laws governing the national interest of the country including national defense, criminal law, and national postal services while health care, public education, and highways are part of provincial government legislation.
In the given question, Mrs. Brown who is a lawyer by profession wants to create a company to operate her business activities in all provinces and territories - this is a situation which requires provincial law to be implemented since it concerns the business formation and it's operation for an individual and hence doesn't concerns the national interest of the country.