A good example of vertical integration is a

Select one:

A$.$ hospital opening up a nursing home for the aged.

B$.$ railroad company acquiring a trucking company specializing in long$-$haul freight.

C$.$ crude oil refiner purchasing a firm engaged in drilling and exploring for oil.

D$.$ global public accounting firm acquiring a small local or regional public accounting firm.

E$.$ large supermarket chain getting into convenience food stores.