Kirsten manages the infrastructure that hosts her company's CRM platform. She currently has a production environment that all of the users access. However, she was recently reading about the concept of creating a second production environment where patches and updates are applied and then traffic is shifted over to the second environment once it has been tested. Which of the following describes the methodology that she is considering implementing? a. Duplicate deployment b. Canary deployment c. Blue-green deployment d. Rolling deployment