The correct answer is option 'A' - a progress file.

Explanation:
A production planning and control system is a set of tools and processes used by manufacturing companies to plan, schedule, and control their production operations. It involves various files and documents that are used to store and manage information related to production planning and execution.

Let's examine each of the given options to understand their roles in a production planning and control system:

a) Progress File:
A progress file is not typically part of the planning files in a production planning and control system. It refers to the documentation of the progress made during the production process, such as the completion status of work orders, production schedules, and reports on the actual production achieved. While monitoring progress is an essential aspect of production planning and control, it is not considered a planning file itself.

b) Work Center Master File:
A work center master file is a key planning file in a production planning and control system. It contains information about each work center or machine in the manufacturing facility, including its capacity, capabilities, availability, and assigned personnel. This file helps in scheduling and allocating work orders to the appropriate work centers based on their capacity and capabilities.

c) Item Master File:
An item master file is another crucial planning file in a production planning and control system. It contains information about the various items or products manufactured by the company, including their specifications, bill of materials (BOM), and inventory levels. This file helps in determining the material requirements, planning production quantities, and managing inventory.

d) Routing File:
A routing file is an essential planning file in a production planning and control system. It contains the sequence of operations or steps required to manufacture a product, along with the corresponding work centers or machines involved at each step. This file helps in defining the production process, estimating the production time, and scheduling the operations.

In summary, while a progress file is important for monitoring the progress of production, it is not considered a planning file in a production planning and control system. The other options, including the work center master file, item master file, and routing file, are all significant planning files that play crucial roles in managing and controlling production operations.