A hosted service is the correct answer for where to execute the release agents for the investment planning application suite.

Running release agents in a hosted service centralizes pipeline execution and provides isolation and consistent runtime environments and access controls and audit logs which are required for reliable and repeatable releases. A hosted CI/CD service can scale and integrate with source control and deployment targets while keeping credentials and secrets out of developer machines.

Using a hosted service also enables automated triggers from commits and pull requests and it provides centralized logging and rollback capabilities which align with the enterprise release management needs described in the case study.

Developers' workstations are wrong because they are ephemeral and inconsistent and they do not provide the centralized control or auditing needed for production releases and they create security and availability risks if releases depend on individual machines.

Source control repository is wrong because a repository stores code and can trigger pipelines but it does not execute release agents itself and running agents inside the repo would mix concerns and weaken separation of responsibilities and security best practices.

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