This option is available under :

• Login »  My Surveys »  (Select Survey) »  Survey Control »  Finish Options

Users will be automatically redirected to the specified web site (of your choice) upon the completion of the survey.

How can I remove the redirection link from the Thank you page?

If you do not want to place the Redirect link on this page then remove the Thank you Text from the "Text For the Link (Max Length 255)" box.