Answer D is correct. In many situations, it is a good idea to disable indexes while performing data imports. To do so, you use the ALTER INDEX command. The DISABLE option turns the index off to allow for more immediate data imports. To enable the index, you need to rebuild it. In particular, clustered indexes require data reordering when importing has been completed. To enable indexes, you use the REBUILD option. Dropping and creating indexes would work, although it is unnecessary because the disable functionality is available.
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