One Reason a Computer Manufacturer May Make Its Own Microchips

One reason a computer manufacturer may make its own microchips rather than buy them is that

A) it can maintain control over the quality during production
B) the total cost of components is the same as the price of chips purchased from a chip manufacturer
C) firms do not make high-quality microchips
D) managers at the computer firm place a high value on their time
E) firms do not produce goods for the market that can be made in-house