Answer:
commercialization
Step-by-step explanation:
Based on this information it seems that Natalie and Chris are in the commercialization phase of the new-product development process. This phase is the process of introducing a new product or production into the market. Since Natalie and Chris finished testing the market and determined that the product no longer needs any changes they are now in the commercialization phase, which is also the last phase in the product development process.