According to the passage, the decisive factor in maintaining a firm’s competitive advantage is______.

A．Meet his anthropology teacher.
B．Lend him her magazine when she’s done with it.
C．Come over to his house after class.
D．Help him study for an anthropology test.

A．The local Africans are peace-loving people.
B．Soda bottles are very precious in some remote areas.
C．A trivial thing may sometimes bring about undesirable consequences.
D．Caution must be taken in introducing new technology.