What is the primary purpose of the O'Hare Airport Badge?

The primary purpose of the O'Hare Airport Badge is to grant authorized individuals access to secure areas of the airport. This is crucial for maintaining security protocols at busy airports like O'Hare, where certain areas are limited to personnel who have undergone background checks or specific training. The badge serves as a formal identifier of those who are permitted to enter restricted zones, such as ticketing areas, boarding gates, and baggage handling zones. This not only enhances security but also ensures that airport operations run smoothly by allowing only qualified individuals to access sensitive locations.

In contrast, the other choices do not accurately reflect the badge's primary function. While it might be beneficial for public relations for some employees to be identified, that is not its main purpose. Similarly, the badge is not designed to provide free parking or allow unrestricted access, as both of these could pose security risks. The focus is firmly on security and access control, making the correct answer clear.