Your customer runs a web service used by e-commerce sites to offer product recommendations to users. The company has begun experimenting with a machine learning...

Your customer runs a web service used by e-commerce sites to offer product recommendations to users. The company has begun experimenting with a machine learning model on Google Cloud Platform to improve the quality of results.
What should the customer do to improve their model's results over time?

A. Export Cloud Machine Learning Engine performance metrics from Stackdriver to BigQuery, to be used to analyze the efficiency of the model. B. Build a roadmap to move the machine learning model training from Cloud GPUs to Cloud TPUs, which offer better results. C. Monitor Compute Engine announcements for availability of newer CPU architectures, and deploy the model to them as soon as they are available for additional performance. D. Save a history of recommendations and results of the recommendations in BigQuery, to be used as training data.