The data is validated through a panel of over 5 million Google Opinion Rewards volunteers.

• 100,000
• 1 million
• 500,000
• 5 million

The correct answer is: 5 million

Explanation: When Google identifies potential store visits, an added layer of verification steps in. Selected users from a vast pool of 5 million Google Opinion Rewards volunteers are surveyed regarding their store visits. They detail the specific locations they’ve been to, allowing Google to cross-check actual visits with predicted ones. This feedback is invaluable, allowing Google to continuously refine and enhance its machine learning models, ensuring accuracy.

Read more here: https://support.google.com/google-ads/answer/6100636