Child’s World, a chain of toy stores, has relied on a “supermarket concept” of computerized inventory control and customer self-service to eliminate the category of sales clerks from its force of employees. It now plans to employ the same concept in selling children’s clothes.

The plan of Child’s World assumes that

(A) supermarkets will not also be selling children’s clothes in the same manner

(B) personal service by sales personnel is not required for selling children’s clothes successfully

(C) the same kind of computers will be used in inventory control for both clothes and toys at Child’s World

(D) a self-service plan cannot be employed without computerized inventory control（B）

(E) sales clerks are the only employees of Child’s World who could be assigned tasks related to inventory control......................I completely don't know why is B...I think B is irrevelent to this choice....who can help me....

To make it short: They fired sales people in the toy's department before; now again, they want to fire people in the clothes department.

Does it sound better to you?

请问哪位大侠能翻译下B选项，特别是把 successfully 翻译进去

它到底是什么意思，谢谢。