The application of an unemancipated minor for a beginner's permit, instruction permit, or driver's license must be signed and verified before a person authorized to administer oaths by the father, mother, or guardian or, for all other minors, by a responsible adult who is willing to assume the obligation imposed under this article upon a person signing the application of a minor. Upon the extension of a permit pursuant to Section 56-1-50, authorization by the father, mother, guardian, or a responsible adult is not required.