3. (1) Subject to the provisions of this Ordinance, every male citizen of Bangladesh who has attained the age of eighteen years and has not attained the age of twenty years and possesses educational qualifications not below that of a matriculate shall be liable to render national service. (2) Every male citizen of Bangladesh who, at the commencement of this Ordinance, has attained the age of eighteen years and has not attained the age of twenty years and possesses educational qualifications not below that of a matriculate shall, not later than one month from such commencement, offer himself for national service in such manner and to such authority as may be prescribed. (3) Every male citizen of Bangladesh who, at any time after the commencement of this Ordinance,-(a) being a matriculate, attains the age of eighteen years, or(b) having attained the age of eighteen years, becomes a matriculate,shall, not later than one month from the date on which he attains the age of eighteen years or, as the case may be, becomes a matriculate, offer himself for national service in such manner and to such authority as may be prescribed. (4) Nothing in sub-section (1), sub-section (2) or sub-section (3) shall apply to persons-(a) who are members of any of the Defence Services or civilian armed forces of, or any police force in, Bangladesh or are employed in any of the ordnance factories in Bangladesh; or(b) who, being engaged in any essential service or being students of any medical, engineering or veterinary institution, are declared by the Government, by notification in the official Gazette, to be exempt from the liability to render national service.