Final answer:
Coordination of Benefits (COB) is a system used when an individual has multiple insurance plans. The person in question has two insurances because of their spouse, and they can pay extra to be on their spouse's insurance if they have one. This system allows the individual to have coverage from both plans and reduce their out-of-pocket expenses.
Step-by-step explanation:
The subject you are referring to is Coordination of Benefits (COB). COB is a system used when an individual has multiple insurance plans. In this case, the person has two insurances because of their spouse. The primary plan is billed first, but if the individual has a spouse with a different insurance, they can pay extra to be on their insurance as well. This allows them to have coverage from both plans and reduces their out-of-pocket expenses.