When someone clicks your ad, the actual amount you’re charged will be:

When someone clicks your ad, the actual amount you’re charged will be:

• The minimum needed to hold your ad position or 50% of your maximum cost-per-click (max. CPC) bid, whichever is greater
• The minimum needed to hold your ad position but never less than 50% of your maximum cost-per-click (max. CPC) bid, whichever is greater
• The minimum needed to hold your ad position but never more than 120% of your maximum cost-per-click (max. CPC) bid, whichever is greater
• The minimum needed to hold your ad position, under the maximum cost-per-click (max. CPC) limit

Correct answer is:

• The minimum needed to hold your ad position, under the maximum cost-per-click (max. CPC) limit

Explanation:When someone clicks your ad, the actual amount you’re charged will bethe minimum needed to hold your ad position, under the maximum cost-per-click (max. CPC) limit.

Actual CPC
is often less than max. CPC because with the Google Ads auction, the most
you’ll pay is what’s minimally required to hold your ad position and any ad
formats shown with your ad, such as sitelinks.

Read more here: https://support.google.com/adwords/answer/6297?hl=en