The correct answer is C – Re-train the model with fresh data. AWS SageMaker Model Monitor is designed to detect data drift, feature drift, and model quality degradation in real-time. When drift exceeds a set threshold, AWS recommends initiating a retraining workflow with updated data to restore model accuracy. According to AWS documentation, data drift indicates that the distribution of incoming data has changed significantly from the original training dataset—often due to new user behaviors, market changes, or seasonal patterns. Restarting the endpoint (A) does not address degraded model performance. Adjusting sensitivity (B) suppresses the alert but does not fix the underlying issue. Experiments tracking (D) is helpful for monitoring model versions but is not corrective. Retraining ensures the model adapts to new data patterns and continues to perform reliably, which is the AWS-endorsed response to drift detection alerts.

Referenced AWS Documentation:

Amazon SageMaker Model Monitor – Detecting Drift

AWS ML Ops Best Practices – Continuous Retraining