What is one requirement to hold a red/blue card?

To hold a red or blue card, one essential requirement is that individuals must have passed the respective red or blue card exam. This exam is designed to ensure that individuals have the necessary knowledge and understanding of the topics covered, which is critical for the effective use and safety associated with the activities that the card pertains to. The successful completion of this examination demonstrates competency and readiness to participate in the relevant activities, which is a foundational requirement for obtaining the card.

The other options, while they may reflect valid criteria in different contexts, do not directly pertain to the specific requirement for obtaining the red or blue card. For instance, age restrictions may apply differently across various regulations, residency requirements can vary based on local laws, and educational qualifications may not be universally necessary for all card holders. Thus, passing the exam stands out as the clear and specific requirement related to the red and blue cards.