What deployment strategy uses feature switches to enable incomplete features in production environments?

The correct choice, which identifies the deployment strategy that utilizes feature switches to enable incomplete features in production environments, is dark launching. This technique allows developers to release new features to a portion of users without exposing them fully.

With dark launching, incomplete or experimental features can be activated via feature flags or switches, allowing teams to test and gather data on those features' performance or user interaction without disrupting the entire system or overwhelming users. This strategy is particularly valuable because it facilitates real-world testing conditions while still allowing for gradual rollouts and adjustments based on user feedback and behavior.

In contrast, blue-green deployment focuses on maintaining two identical production environments to reduce downtime during updates. Canary testing involves rolling out new changes to a small subset of users before full deployment, primarily to mitigate risk. A/B testing compares two versions of a webpage or app functionality to determine which performs better, but it doesn't specifically address incomplete features in production like dark launching does.