Based on Snowflake documentation and the community consensus (80% support for ABD with higher upvotes), the Cloud Services layer handles authentication (A), resource management (B), and query parsing and optimization (D). Authentication is explicitly listed in Snowflake's documentation as a Cloud Services responsibility. Resource management includes infrastructure management, which is part of Cloud Services. Query parsing and optimization occur in Cloud Services before execution is delegated to virtual warehouses. Option C (virtual warehouse caching) is incorrect as caching occurs at the virtual warehouse level, not Cloud Services. Option E (query execution) is performed by virtual warehouses. Option F (physical storage) is handled by the storage layer, not Cloud Services.