The market for (manufactured goods) is (which) economists call "imperfect," because each company has its own style; and all of the arts of advertisement and salesmanship are devoted (to making) it (even more imperfect) by attracting buyers to particular brand names. A. manufactured goods B. which C. to making D. even more imperfect

A．the ability to adjust one’s behavior in light of the behavior of others
B．the degree of stability one can create in one’s immediate environment
C．the accuracy with which one can predict future events
D．the success one achieves in conserving and storing one’s resources