The reason much refrigerated food spoils is that it ends up out of sight at the back of the shelf. So why not have round shelves that rotate? Because such rotating shelves would have just the same sort of drawback, since things would fall off the shelves' edges into the rear corners.
Which of the following is presupposed in the argument against introducing rotating shelves?
(A) Refrigerators would not be made so that their interior space is cylindrical.
As the Evidence or the conclusion provided by the Argument is that THINGS WILL FALL OF THE REAR EDEGES.
This implies that the refri. will still have the edges that can only happen if the INTERIOR is not CYLYNDRICAL--> (A) states that clearly
So Pick A