You are building an ML model to predict customer churn for a subscription service. You have trained your model on Vertex AI using historical data, and deployed it to a Vertex AI endpoint for real-time predictions. After a few weeks, you notice that the model's performance, measured by AUC (area under the ROC curve), has dropped significantly in production compared to its performance during training. How should you troubleshoot this problem?

A. Monitor the training/serving skew of feature values for requests sent to the endpoint. B. Monitor the resource utilization of the endpoint, such as CPU and memory usage, to identify potential bottlenecks in performance. C. Enable Vertex Explainable AI feature attribution to analyze model predictions and understand the impact of each feature on the model's predictions. D. Monitor the latency of the endpoint to determine whether predictions are being served within the expected time frame.