- Enhanced CPC
- Maximize Clicks
- Manual Max CPC
- Target Return On Ad Spend (tROAS)
The correct answer is: Target Return On Ad Spend (tROAS)
Explanation: For a client running a Performance Max campaign with Maximize Conversion Value as their primary bid strategy, Target Return On Ad Spend (tROAS) would make a good optional secondary bid strategy. tROAS automatically adjusts bids to maximize conversion value based on the specified return on ad spend, effectively enhancing the potential for higher returns.