25. (1) No person under the age of eighteen years shall hold, or be granted, a conductor's licence. (2) The licensing authority may refuse to grant a conductor's licence-(a) if the applicant does not possess the requisite qualifications;(b) if his knowledge of the provisions of the Ordinance and of the ¹[regulations] and of the duties and powers of a conductor thereunder is inadequate to enable him to perform the duties of a conductor;(c) if the medical certificate produced by the applicant discloses that he is unfit to act as a conductor;(d) if any previous conductor's licence or driving licence held by the applicant was revoked; and(e) if the character or physique or conduct of the applicant is such as to render him an unsuitable person to hold a conductor's licence.