The hybrid cloud model is the most suitable for the described scenario. It allows for a combination of local (private) cloud infrastructure with remote (public) cloud services. This model supports hosting the primary workloads in a local data center, utilizing remote data centers for backups, and provides the flexibility to scale out to a public cloud provider when necessary. The hybrid cloud model offers the benefits of both private and public clouds, including security, scalability, and flexibility, which aligns with the organization's requirements.
References: For more information on cloud deployment models and their use cases, you can refer to the Cisco Data Center Core Technologies (DCCOR) study materials or the official Cisco documentation on cloud solutions.