You have an application that runs on Cloud Run. You want to use live production traffic to test a new version of the application, while you let the quality assurance team perform manual testing. You w

Deploying the application as a new Cloud Run service creates a completely separate service, which is less ideal for managing traffic splitting and rollbacks of *different versions of the same application* compared to using revisions within a single service.

Deploying a new Cloud Run revision with a tag (e.g., 'v2-test') and the `--no-traffic` option allows you to deploy the new version without immediately sending production traffic to it. This creates a dedicated URL for the tagged revision, enabling the QA team to perform manual testing in isolation before exposing it to live users.

Deploying a new revision without a tag while using `--no-traffic` would make it harder for the quality assurance team to reliably access and perform manual testing on that specific revision, as a tag provides a stable, identifiable URL.

After deploying the new revision with `--no-traffic`, you can then use Cloud Run's traffic management feature to split production traffic, routing a percentage to the new version. This enables canary testing with live production traffic, limits potential impact, and provides an immediate rollback mechanism by simply adjusting traffic percentages back to the stable version.

Deploying the new application version and splitting traffic is part of the solution (covered by D), but it omits the crucial initial step of deploying *without traffic* and with a tag (covered by B) to enable isolated manual QA testing before live traffic exposure.