What should be done when answers to the security questions are forgotten?

Issue

My users keep forgetting their answers to the security questions is there a way to disable this? Also is there an alternative to the forgot password option?

Liferay already sends a password reset link when users click on Forgot Password, provided that they pass the captcha check. If security questions are enabled, then Liferay will also ask a security question.
If you want to disable security questions, you would go to Control Panel -> Instance settings -> User Authentication, click on Reminder Queries. You can uncheck Enabled and click on Save.
From then on, if a user clicks on Forgot Password, then only a captcha test is required.