Option C is the correct answer because the MERGE command is specifically designed to handle both incremental updates and deletions from a source table to a target table efficiently. It ensures data consistency by synchronizing the target table with the source table, including processing deletions, which is crucial for the given requirements. Option A, while ensuring data consistency, does so at a higher operational cost and is not efficient for frequent updates. Option B fails to handle deletions, leading to data inconsistency. Option D, although efficient for loading data, cannot process deletions, making it inadequate for the scenario described.