A. Combining masking policies and external tokenization allows for complete elimination of PCl data from the Snowflake environment, even during processing.

B. Masking policies and external tokenization provide independent layers of security. If one is compromised, the other still provides protection.

C. Tokenization ensures compliance with PCl DSS standards, while masking policies are primarily useful for internal access control and obfuscation for development environments. Using both doesn't increase security.

D. Column-level security can be used to restrict access to the tokenization UDF itself, ensuring that only authorized users can perform tokenization or detokenization operations.

E. The use of both techniques increases query performance drastically.