At the Walmart warehouse where you are cross$-$training, boxes packed for shipping are periodically checked to ensure that they contain the items listed on the shipping statement.

Which form of operational control is this?

Preaction

Screening

Preliminary

Postaction

At its warehouses, Walmart receives items manufactured elsewhere that it will stock and sell in its stores. Because Walmart doesn't actually control the manufacturing of the products it sells, could be the most critical type of operational control for Walmart.