Big businesses .

operated across large areas of the country
controlled all phases of production
had small start-up costs
specialized in one phase of production

Big businesses "controlled all phases of production" .

Option: B

Explanation:

The big businesses are immense because they believe in producing all the basic requirements for leading product of the company. For an instance like a firm of manufacturing snacks or fast food, which is a highlighted product of an organization, will also focus on producing breads, butter, milk, etc. production which are composition of different commodities.

Applying this strategy business individuals not only earn profit and save money, but also spread their market in large scale by controlling all the phases of production. The turnover increases more by production and selling rather than building franchises across large areas only. Combination of both can lead a firm to top level.