You are tasked with analyzing website clickstream data stored in a Snowflake table named 'clickstream_data'. The table contains a 'variant' column named 'event data' that holds JSON data representing various events like 'page view', 'button click', and 'form submission'. You need to extract the 'page_url' from 'page_view' events, the 'button id' from 'button click' events, and the 'form id' from 'form submission' events. Design the most efficient Snowflake SQL query to achieve this, considering the performance implications of variant parsing and filtering. Assume the 'event_type' is directly available within the variant object as well. Which of the following queries would be most efficient?

Correct Answer: C
Option C is the most efficient. Snowflake's native variant access is generally faster than using 'PARSE_JSON' Also, explicit casting to VARCHAR ensures consistency in the output data type. Option A although correct will produce an output that is of variant type for all fields. Option B is incorrect because if none of the when conditions matches, then it returns NULL. Option D uses PARSE JSON unneccessarily making it slower. Option E uses GET which is used to extract data from an object within VARIANT and not to directly evaluate the VARIANT column.