When a Snowflake virtual warehouse is resized, the data cached in the warehouse is not lost. This is because the cache is maintained independently of the warehouse size. Resizing a warehouse, whether scaling up or down, does not affect the cached data, ensuring that query performance is not impacted by such changes.
References:
* [COF-C02] SnowPro Core Certification Exam Study Guide
* Snowflake Documentation on Virtual Warehouse Performance1

Directory tables in Snowflake are used to store metadata about data files in a stage. They are not separate database objects but are conceptually similar to external tables. Directory tables do not have grantable privileges of their own

A multi-cluster virtual warehouse in Snowflake is designed to handle high concurrency and workload demands by allowing multiple clusters of compute resources to operate simultaneously. The correct scenario to use a multi-cluster virtual warehouse is:
* A. When queuing is delaying query execution on the warehouse: Multi-cluster warehouses are ideal when the demand for compute resources exceeds the capacity of a single cluster, leading to query queuing. By enabling additional clusters, you can distribute the workload across multiple compute clusters, thereby reducing queuing and improving query performance.
This is especially useful in scenarios with fluctuating workloads or where it's critical to maintain low response times for a large number of concurrent queries.
References:
* Snowflake Documentation: Multi-Cluster Warehouses at Snowflake Documentation

Periodic rekeying of micro-partitions is a feature that requires the Enterprise Edition of Snowflake or higher. This feature is part of Snowflake's comprehensive approach to encryption key management, ensuring data security through regular rekeying1. Reference: [COF-C02] SnowPro Core Certification Exam Study Guide

https://docs.snowflake.com/en/user-guide/semistructured-intro.html#label-loading-semi-structured-data A VARIANT stores semi-structured data in Snowflake. It can store a value of any other type, including OBJECT and ARRAY.
The maximum length of a VARIANT is 16 MB.
A Snowflake ARRAY is similar to an array in many other programming languages. An ARRAY contains 0 or more pieces of data. Each element is accessed by specifying its position in the array.