A license applicant who fails the licensing exam on their first attempt:

The correct choice indicates that a license applicant who fails the licensing exam on their first attempt must wait at least 30 days before they can attempt the exam again. This waiting period is designed to allow candidates to adequately prepare for a second attempt, as immediate retakes may not give them enough time to improve upon their previous performance. State regulations often include such provisions to ensure that applicants are better equipped to pass with each subsequent attempt.

In this context, the other options do not align with the established rules regarding retaking the exam. For instance, being able to retake the exam immediately would not provide the necessary time for additional study and preparation. Permanent disqualification after a first failure is too severe and would negate the opportunity for improvement that such a policy provides. Additionally, while some states might have training requirements following multiple failures, the option that states additional training is mandatory after the first attempt is typically not enforced or required.

Overall, the requirement for a 30-day wait period is a common regulatory approach to support candidates' success in obtaining their license.