单选题 From the last paragraph we learn ______.

A、 direct advertising is the best way to promote a product
B、 companies are trying to find the best way to sell their products
C、 advertising is becoming enriched by the research in this area
D、 old ways of advertising is giving ways to new ways of doing it

【正确答案】 C

【答案解析】由最后一段的描述可以得到C，其它答案显然与描述的事实不符。