[单项选择]下列细胞因子中对造血细胞起负向调控作用的是（）
A. SCF（干细胞因子）
B. TGF-β（转化生长因子β）
C. IL-11
D. IL-3
E. TPO（血小板生成素）

The appeal of advertising to buying motives can have both negative and positive effects. Consumers may be convinced to buy a product of poor quality or high price because of an advertisement. For example, some advertisers have appealed to people’ s desire for better fuel economy for their cars by advertising automotive products that improve gasoline mileage. Some of the products work. Others are worthless and a waste of consumers ’money.
Sometimes advertising is intentionally misleading. A few years ago, a brand of bread was offered to dieters (节食者)with the message that there were fewer calories (热量单位，卡路里)in every slice. It turned out that the bread was not dietetic (适合节食的), but just regular bread. There were fewer calories because it was sliced very thin, but there were the same number of calories in every loaf.
On the positive side, emotional appeals may respond to a consumer’ s real concerns, considering fire insurance. Fire insurance
A. sometimes advertisements really sell what the consumer needs
B. advertisements occasionally force consumers into buying things they don' t need
C. the buying motives of consumers are controlled by advertisements
D. fire insurance is seldom a worthwhile investment