When Gary got in line to pay for his groceries, he picked the line in which he was required to scan the prices of his groceries and bag them himself. He was pleased with his use of a$($n$)\_\_\_\_\_\_\_$ because he could take extra care in getting his eggs home unbroken without the risk of a store bagger dropping a melon on top of them.

Multiple Choice

SST

Promotable differentiator

Robot

ISP

Ergonomic layout