A software company is migrating a single-page application from on-premises servers to the AWS Cloud...

AWS Amplify’s most direct support for GraphQL APIs is through AWS AppSync, and the Amplify CLI can generate and configure an AppSync GraphQL API directly from a schema with minimal setup. The requirement says the API already has an existing GraphQL schema, and the goal is to migrate it with the least configuration effort.

Option D is the simplest: run amplify add api, choose GraphQL, and provide the existing schema. Amplify then provisions the AppSync API, sets up the schema, creates the backend resources (depending on chosen data sources), and wires the configuration into the Amplify project so the SPA can consume the API.

Option A is incorrect because it selects REST and does not align with an existing GraphQL schema.

Option B is incorrect because API Gateway is not the native GraphQL service and would require additional mapping/proxy logic—more configuration.

Option C can be valid if an AppSync API already exists and you want to import it, but the question asks to “migrate the API along with the application” with least configuration. Creating it directly in Amplify is typically less configuration than creating separately and importing.

Therefore, using Amplify CLI to add a GraphQL API and supply the existing schema is the least-config approach.