The secret agent kept looking back because he was afraid of __________.

A．The relationship between market investigation and sales promotion is just as that of the lips and teeth.
B．It is impossible to succeed in selling a product without market investigation.
C．There are various ways of making market investigation.
D．Production goes before market investigation.

A．Consumers will put off buying things if they expect prices to decrease.
B．Consumers will spend their money quickly if they expect prices to increase
C．The price condition has an influence on consumer behavior
D．Traditional assumptions about earning and spending are reliabl