Answer: Blue/green deployment and canary testing

The requirements are to reduce deployment complexity and minimize rollback duration while testing real production traffic with gradual user exposure. - **Blue/green deployment** minimizes rollback complexity and duration by maintaining two identical environments (e.g., 'blue' for current and 'green' for new). Switching traffic between them is instant, simplifying rollbacks. - **Canary testing** gradually exposes the new version to a small subset of users (e.g., 5%), then incrementally increases traffic (e.g., 20%, 50%, 100%) while monitoring for issues. This allows testing real production traffic with controlled risk. Option A (Recreate deployment and canary testing) fails because recreate deployments cause downtime and slow rollbacks. Option C (Rolling update and A/B testing) involves incremental instance updates but rollbacks are complex and slow; A/B testing focuses on feature comparison, not gradual stability testing. Option D (Rolling update and shadow testing) has similar rollback issues; shadow testing mirrors traffic without affecting users, so it doesn't gradually expose users. Thus, only option B meets both requirements.

Author: LeetQuiz Editorial Team