• Email [email protected] to find out why it wasn’t approved
• Open and then resubmit the ad
• Click “Re-review display ad”
• Edit your ad so it complies with Google policy and re-save it

The correct answer is: Edit your ad so it complies with Google policy and re-save it

Explanation: To fix a disapproved ad, read the policy closely and then edit your ad so that it complies with the policy.
Read more here: https://support.google.com/google-ads/answer/1704381