Final answer:
Unit-serial numbering is a system in which each encounter with a healthcare facility is assigned a unique numerical identifier.
Step-by-step explanation:
The correct answer is d) Unit-serial numbering.
Unit-serial numbering is a system in which each encounter with a healthcare facility is assigned a unique numerical identifier. In this system, the unit number is assigned first and then followed by a sequential serial number. This helps the healthcare facility keep track of each patient's visits and encounters.
For example, if a patient visits a healthcare facility for the first time, their identifier might be 001-001. If they visit again, their identifier might be 001-002, and so on. This numbering system is useful for maintaining accurate records and organizing patient information.