Answer:
With personal selling, the salespeople go out into the market and explain the benefits of a product in person. This is what businesses prefer because they have to make large scale purchase decisions and so would like to develop a personal relationship with the supplier that will enable them to have all the information they need.
There is also a need for customization in the business market because business might want the goods supplied to be adjusted in a certain way to enable them process and sell it.
This is different from the consumer market where purchases are not as large scale and there is little need to customize goods. Advertising to the general public is therefore better because the goods would be standard and there would be no need for personal relationships as in the business market.