Which option allows a customer to purchase an extension of the original warranty?

The option that allows a customer to purchase an extension of the original warranty is the service plan. A service plan typically covers repairs, maintenance, or enhancements beyond the standard warranty period, giving customers peace of mind and extended protection for their purchase. This can be particularly valuable for products that may require additional support after the initial warranty expires.

In contrast, other options like a credit plan are primarily financial arrangements to facilitate payments, while layaway involves reserving an item by making payments over time without taking immediate possession. Insurance generally covers unforeseen losses or damages but operates differently than a service plan, which focuses specifically on extending product support and warranty coverage.