A company wants to move its environment from on premises to the cloud without vendor lock-in. Which of the following would BEST meet this requirement?

DBaaS uses provider-specific managed database engines, connection APIs, and backup mechanisms that tie the organization tightly to a single vendor's implementation.

SaaS is fully managed by the vendor and hosted entirely on their infrastructure, giving the customer no control over portability or migration paths.

IaaS delivers fundamental compute, storage, and networking using industry-standard technologies such as virtual machines, virtual networks, and block storage, which can be reproduced on any major cloud provider with minimal rework. Because IaaS does not depend on proprietary managed services, platform-specific runtimes, or vendor APIs, workloads can be migrated between providers by redeploying the same OS images and configurations. This makes IaaS the cloud service model that best satisfies a requirement to avoid vendor lock-in.

PaaS abstracts the underlying infrastructure but relies on vendor-specific runtimes, deployment pipelines, and APIs, making it significantly harder to migrate to a different provider.