The correct answer is B. Only one refresh will run at a time .
Failover groups can be refreshed on a schedule to replicate supported account objects and database objects to target accounts. Snowflake does not run overlapping refresh operations for the same failover group.
Why B is correct:
If a scheduled refresh is still running, Snowflake does not start another concurrent refresh for the same failover group. Refresh operations are managed so that only one refresh runs at a time.
Why the other options are incorrect:
A). Multiple refreshes for the same failover group do not run concurrently.
C). Refreshes still require the appropriate privileges and configured replication/failover group permissions.
D). A delayed or long-running refresh does not mean the next refresh is automatically canceled in the way stated. The key behavior is that refreshes do not overlap.
Official Snowflake documentation reference:
Snowflake documentation for replication and failover groups explains that scheduled refreshes are managed by Snowflake and that refresh operations do not run concurrently for the same group.
Reference: Snowflake Documentation - Replication and failover groups; Snowflake Documentation - Failover group refresh; SnowPro Core Study Guide - Snowflake Account and Resource Management.

Explanation
Characteristics of a VARIANT
A VARIANT can store a value of any other type, including OBJECT and ARRAY. The maximum length of a VARIANT is 16 MB.
https://docs.snowflake.com/en/sql-reference/data-types-semistructured.html#:~:text=VARIANT-,Characteristics

In owner's rights stored procedures, certain commands are restricted to maintain security and integrity. The SHOW and DESCRIBE commands are limited because they can reveal metadata and structure information that may not be intended for all roles.