You have a list of customers and their companies and would like to join company data (left) to the customer records (right) using the FeatureJoiner. You want to output only records that found a match. Which Join Mode would you use?

• A. Left
• B. Right
• C. Inner
• D. Full

Answer: (C)

When joining two feature streams, the join mode determines which features survive when there isn’t a perfect match on both sides. To output only records that have a corresponding match, you want the mode where only features with a matching pair on both inputs are kept. That is inner join: it merges attributes only for features that have a matching key on the left (company data) and the right (customer records) and discards any unmatched features.

Left would keep all customers even if there’s no company match (unmatched customers would carry nulls for company attributes). Right would keep all companies regardless of whether a customer exists for them. Full would keep all features from both sides, with nulls where matches are missing. Since the goal is strictly matched records, inner join is the correct choice.