You have a large amount of historical data in an operating system file. Some analysts in your organization need to query this data. The file is too large to load into your current database. Which is the most effective method to accomplish the task？（）

• A、Upgrade the hardware/memory to accommodate the data.
• B、Load the data into your database by using the PARALLEL clause.
• C、Give analysts DBA privilege， so that they can query DBA_EXTERNAL_TABLES.
• D、Use an external table so you can have the metadata available in your database， but leave the data in the operating system files.