The application for an operator's license must be signed by the parent or guardian when the applicant is under the age of?

In Ohio, the requirement for a parent or guardian to sign the application for an operator's license applies to applicants who are under the age of eighteen. This rule is in place to ensure that a responsible adult, typically a parent or guardian, provides consent for the minor to operate a vehicle. Since individuals who are eighteen and older are considered adults, they can independently apply for a driver’s license without needing parental consent. Hence, the correct answer appropriately highlights that anyone younger than eighteen must have their license application signed by a parent or guardian.