The correct answer is Cloud Deployment Manager. This tool is specifically designed for defining, deploying, and managing GCP resources using declarative configuration files (YAML or Python). It enables automated and repeatable infrastructure management.

• Cloud Build is a CI/CD service focused on building, testing, and deploying applications, not infrastructure management.
• Cloud Storage provides object storage capabilities, not infrastructure as code functionalities.
• Cloud Functions is a serverless platform for executing event-driven functions, unrelated to infrastructure management.

Thus, Cloud Deployment Manager stands out as the dedicated tool for IaC in GCP.