You should add a Product feed extension to a video action campaign to drive more conversions in a simple and cost-effective way for a single automated campaign.

• Lead form
• Sitelinks
• Product feed
• Location

The correct answer is: Product feed

Explanation: To drive more conversions in a simple and cost-effective way for a single automated video action campaign, you should add a product feed extension. This allows you to show shoppable product imagery below your video ads, inspiring users to make a purchase and drive more conversions. On average, advertisers that add product feeds to their Video action campaigns achieve over 60% more conversions at a lower cost. The requirements include setting up a product feed in Merchant Center, including at least 4 products, including images for each product, and complying with Shopping ad policies.

Read more here: https://support.google.com/google-ads/answer/11371384