Explain difference between schema-on-read and schema-on-write.

• A. Schema-on-read validates data at load; schema-on-write validates at query time.
• B. Schema-on-read requires data to be stored without any schema; schema-on-write enforces a schema during query.
• C. Schema-on-read applies schema at query time; schema-on-write enforces schema upon data load.
• D. Schema-on-read is only for unstructured data; schema-on-write is only for structured data.

Answer: (C)