Final answer:
The best cloud-hosting option for the described needs is Single-tenancy PaaS because it offers a dedicated, customizable environment suitable for large databases and aligns with the goal to reduce datacenter reliance.
Step-by-step explanation:
For a team that is at the beginning stages of designing a new, large database-dependent enterprise-wide application and looking to save money while reducing reliance on a datacenter, the cloud-hosting option that would best meet these needs is Single-tenancy Platform as a Service (PaaS). This option allows for hosting large databases in the cloud and provides a dedicated infrastructure for the application. It offers customized environments that can meet specific requirements, which is beneficial for enterprise-level applications with large databases.
Unlike Multi-tenancy Software as a Service (SaaS) which serves multiple customers on a single platform, single-tenancy provides isolated environments which may be important for security, performance, and customization considerations. Hybrid Infrastructure as a Service (IaaS) may provide a similar level of dedication and control but typically involves some level of on-premises infrastructure, which the CIO has advised to move away from. Community IaaS shares infrastructure between similar organizations and wouldn't provide the level of customization and control that a single-tenant environment offers.