A mechanized factory with over 3000 separate conveyor belts wants to minimize the cost associated with maintenance, repair, and replacement of these belts. The conveyer belts currently are composed vulcanized rubber around a cotton web base, but the factory owners are investigating new plastic polymer design. For any given size belt, the costs for belts of the two compositions are comparable. Compared to the current rubber/cotton belts, the plastic polymer belts are lighter and easier to move, so operating the conveyor belts made of plastic polymer would consume less electric energy. A change from rubber/cotton belts to plastic polymer belts would require minor modification to some of the drive cylinders of the conveyor belts, but the costs of these changes are negligible. Which of the following would it be most useful to know in determining whether switching to the plastic polymer conveyor belts would be likely to help minimize the factory's cost related to its conveyor belt system? ['Whether other mechanized factories with comparable number of conveyor belts in their systems have switched from rubber/cotton to plastic polymer conveyor belts.', 'Whether the crew that currently maintains the conveyor belts knows how to perform the modification to the drive cylinders necessary to switch to plastic polymer belts.', 'Whether a typical plastic polymer conveyor belt has an approximate serviceable life as least as long as the typical rubber/cotton belt of the same size and shape.', 'Whether, in remodeling, the factory plans to increase the total number of conveyor belts in its mechanized system.']