Answer:
Product
Step-by-step explanation:
A product form of organizational structure refers to the framework wherein an organization is structured based upon it's products and divided and segregated into product divisions.
In such cases, each product division would function independently and look after it's affairs relating to it's product. This form of organizational structure is resorted to when some of the products of an organization gain strategic importance and need to be carefully looked after.
In the given case, the CEO divided each of firms three brands and assigned the brands their own chief executive, to assume responsibility of the operational efficiency of the brands under them. This represents a product form of organizational structure.