In Snowflake, shares are used to share data across different Snowflake accounts securely. When you create a share, you can include various database objects that you want to share with consumers. According to Snowflake's documentation, the types of objects that can be shared include tables, secure views, secure materialized views, and streams. Secure functions and stored procedures are not shareable objects. Tasks also cannot be shared directly. Therefore, the correct answers are streams (C) and tables (D).
To share a stream or a table, you use the GRANT statement to grant privileges on these objects to a share. The syntax for sharing a table or stream involves specifying the type of object, the object name, and the share to which you are granting access. For example:
GRANT SELECT ON TABLE my_table TO SHARE my_share; GRANT SELECT ON STREAM my_stream TO SHARE my_share; These commands grant the SELECT privilege on a table named my_table and a stream named my_stream to a share named my_share. This enables the consumer of the share to access these objects according to the granted privileges.
Reference: Snowflake Documentation on Shares and Database Objects (https://docs.snowflake.com)

The purpose of an External Function in Snowflake is to call code that executes outside of the Snowflake environment. This allows Snowflake to interact with external services and leverage functionalities that are not natively available within Snowflake, such as calling APIs or running custom code hosted on cloud services3.
https://docs.snowflake.com/en/sql-reference/external-functions.html

Automatic Clustering is a feature that allows users to control the organization of data within micro-partitions in Snowflake. By defining clustering keys, Snowflake can automatically reorganize the data in micro-partitions to optimize query performance1.

The function that provides access to download unstructured data from a Snowflake stage is:
* C. GET_PRESIGNED_URL: This function generates a presigned URL for a single file within a stage.
The generated URL can be used to directly access or download the file without needing to go through Snowflake. This is particularly useful for unstructured data such as images, videos, or large text files, where direct access via a URL is needed outside of the Snowflake environment.
Example usage:
SELECT GET_PRESIGNED_URL('stage_name', 'file_path');
This function simplifies the process of securely sharing or accessing files stored in Snowflake stages with external systems or users.
References:
* Snowflake Documentation: GET_PRESIGNED_URL Function at Snowflake Documentation