Your customer has a global chat application that uses a multi-regional Cloud Spanner instance. The application has recently experienced degraded performance aft...

Your customer has a global chat application that uses a multi-regional Cloud Spanner instance. The application has recently experienced degraded performance after a new version of the application was launched. Your customer asked you for assistance. During initial troubleshooting, you observed high read latency. What should you do?

A. Use query parameters to speed up frequently executed queries. B. Change the Cloud Spanner configuration from multi-region to single region. C. Use SQL statements to analyze SPANNER_SYS.READ_STATS* tables. D. Use SQL statements to analyze SPANNER_SYS.QUERY_STATS* tables.