AAn infrastructure as code tool that provisions and manages resources through declarative configuration
BA configuration management tool that installs and updates software on existing running servers
CA container orchestration platform that schedules and scales workloads across a cluster of nodes
DA continuous integration service that builds, tests, and deploys application code on each commit
Why this is the answer
Terraform is an IaC tool that implements the practice — you declare desired state and it provisions it. It is not a configuration-management tool like Ansible, which focuses on configuring existing servers.