Databricks Certified Data Engineer - Associate

Delta Lake tables use the Delta format, which is built on top of Parquet files but adds additional metadata and transaction log capabilities. While Parquet is the underlying storage format for data files, Delta is the overall format that includes:

1. Parquet data files - For storing the actual data
2. Transaction log - For ACID compliance and versioning
3. Metadata - For schema enforcement and evolution

So while option B (Parquet) is technically correct for the underlying data storage, the question specifically asks about the format used for storing Delta Lake Tables, which is the Delta format. The Delta format provides additional features like ACID transactions, time travel, schema enforcement, and unified batch/streaming processing that go beyond basic Parquet storage.