Answer A, adding the support team group to the roles/monitoring.viewer role, is the CORRECT answer. This role grants read-only access to monitoring data for all resources in a project, which allows the support team to monitor the environment but not access the table data.
Answer B, adding the support team group to the roles/spanner.databaseUser role, grants read and write access to all tables in the specified database, which is NOT required for the support team to monitor the environment.
Answer C, adding the support team group to the roles/spanner.databaseReader role, grants read-only access to all tables in the specified database, which would give the support team access to the table data.
Answer D, adding the support team group to the roles/stackdriver.accounts.viewer role, grants permissions to view Stackdriver data for all resources in a project, which is NOT directly related to monitoring the Cloud Spanner environment.