A．They know what they want to buy.
B．They have little money to spend.
C．They talk themselves out of purchases.
D．They shop at the cheapest stores.

A．By a series of injections given before the patient is exposed.
B．By injection immediately after the patient has been stung.
C．Orally for six to ten weeks before the patient is stung.
D．Orally immediately after the patient is stung.

A．The author comments on three different opinions.
B．The author favors one of the three opinions.
C．The author explains an opinion of his won.
D．The author revises someone else"s opinions.