The trick of sale e-mail takes advantage of peoples psychology that______.A．if I buy the g

The trick of sale e-mail takes advantage of peoples psychology that______.

A．if I buy the goods, I will save more money

B．if I don"t buy the goods, there will be no such goods

C．if I buy the goods, I will get a free gift

D．if I don"t buy the goods, they will raise the price

请帮忙给出正确答案和分析，谢谢！