(a) Before issuing an operator's license, the Director of Motor Vehicles may require such proof as he deems necessary that an applicant is physically and mentally fit to operate a motor vehicle. Whenever the Director has reason to believe that the holder of an operator's license is physically or mentally unfit to operate a motor vehicle, he may require the licensee to submit proof of his fitness and he may revoke the license as provided in section 548 of this title if such proof is not furnished.
(b) Before obtaining his first operator's license, an applicant shall undergo a thorough examination before a competent examiner appointed by the Director to test his practical knowledge of, and ability to drive, a motor vehicle, and his knowledge of the laws and regulations applicable to the operation of motor vehicles; Provided, that if such applicant speaks Spanish he shall be granted, upon his request, the privilege of using an interpreter selected by the Director or to take the examination in his own language, whenever practicable.
(c) No operator's license shall be issued unless the Director is satisfied that the applicant is competent to operate a motor vehicle.