The most direct and recommended way to get a granular breakdown of your Google Cloud costs in BigQuery is to enable Cloud Billing data export to BigQuery when you create or manage your Cloud Billing account.
This automatically sets up a daily export of your billing data to a BigQuery dataset you specify.
Option A: Enabling the BigQuery API and managing IAM roles are necessary for interacting with BigQuery, but they don't automatically populate it with Cloud Billing data. Selecting a data location is also important for BigQuery datasets but is a separate step from enabling billing export.
Option B: The BigQuery Data Transfer Service is used for transferring data from various sources into BigQuery, but for Cloud Billing data, the direct export feature is the standard and simpler method.
Option D: Enabling Cloud Billing and linking an account makes billing data available in the Cloud Billing console, but it doesn't automatically export it to BigQuery for detailed analysis. You need to explicitly configure the BigQuery export.
Reference to Google Cloud Certified - Associate Cloud Engineer Documents:
The process of setting up Cloud Billing export to BigQuery is clearly documented in the Google Cloud Billing documentation, which is a fundamental area for the Associate Cloud Engineer certification.
Understanding how to access and analyze billing data is crucial for cost management.

as gcloud config configurations list can help check for the existing configurations and activate can help switch to the configuration.
gcloud config configurations list lists existing named configurations
gcloud config configurations activate activates an existing named configuration Obtains access credentials for your user account via a web-based authorization flow. When this command completes successfully, it sets the active account in the current configuration to the account specified. If no configuration exists, it creates a configuration named default.

A deployment is responsible for keeping a set of pods running. A service is responsible for enabling network access to a set of pods.

https://cloud.google.com/sql/docs/mysql/backup-recovery/backups#can_i_export_a_backup
https://cloud.google.com/sql/docs/mysql/import-export#automating_export_operations