Option B is the correct strategy because it leverages App Engine's traffic splitting feature, allowing you to distribute traffic across different versions within the same service. This approach is ideal for A/B testing and phased rollouts, enabling you to test updates with a subset of users before making them available to everyone. Options A and C involve Kubernetes Engine, which does not natively support traffic splitting for A/B testing without additional setup. Option D suggests creating a new service for each update, which complicates management and is unnecessary since traffic splitting works within the same service. For more details, refer to Google Cloud's documentation on traffic splitting.