You are using flat files as the data source for one of your data warehousing applications. You plan to move the data from the flat file structures to an Oracle database to optimize the application performance. In your database you have clustered tables. While migrating the data， you want to have minimal impact on the database performance and optimize the data load operation. Which method would you use to load data into Oracle database？（）

A. use the external table population
B. use the Oracle Data Pump export and import utility
C. use the conventional path data load of SQL*Loader utility
D. use the direct path data load of Oracle export and import utility