• The query requires a WHERE clause to specify the relevant conversion event type(s)
• The query cannot include user_id as a dimension within the final SELECT statement
• The query does not leverage an audience-specific table
• The query requires a GROUP BY statement

The correct answer is: The query does not leverage an audience-specific table

Explanation: The query SELECT user_id FROM conversions is unsuitable for assembling a rule-based audience in AMC because it does not leverage an audience-specific table. Rule-based audiences in AMC must use specially designated *_for_audiences tables (e.g., conversions_for_audiences) rather than general reporting or measurement tables.

Reference content: From the official Amazon documentation (Rule-based audiences):

“Available data for rule-based audiences queries … The following is a list of AMC data sources that can be used to create AMC rule-based audiences: [table of *_for_audiences datasets] … If you do not use audience-specific tables in the query: statusReason: “Invalid tables in the SQL query: Use audience-specific tables in the query.””