15. Prohibition of dual citizenship. (1) Subject to this article, a Uganda citizen shall not hold the citizenship of another country concurrently with his or her Uganda citizenship. (2) A citizen of Uganda shall cease forthwith to be a citizen of Uganda if, on attaining the age of eighteen years he or she, by voluntary act other than marriage, acquires or retains the citizenship of a country other than Uganda. (3) (a) (b) A person who— becomes a citizen of Uganda by registration; and upon becoming a citizen of Uganda, is also a citizen of another country, shall cease to be a citizen of Uganda unless he or she has— (c) renounced his or her citizenship of that other country; (d) taken the oath of allegiance specified in the Fourth Schedule to this Constitution; (e) made and registered such declaration of his or her intentions concerning residence as may be prescribed by law; or (f) obtained an extension of time for taking those steps and the extended period has not expired. (4) A Uganda citizen who loses his or her Uganda citizenship as a result of the acquisition or possession of the citizenship of another country shall, on the renunciation of his or her citizenship of that other country, become a citizen of Uganda. (5) Where the law of a country, other than Uganda, requires a person who marries a citizen of that country to renounce the citizenship of his or her own country by virtue of that marriage, a citizen of Uganda who is deprived of his or her citizenship by virtue of that marriage shall, on the dissolution of that marriage, if he or she thereby loses his or her citizenship acquired by that marriage, become a citizen of Uganda. 16. National Citizenship and Immigration Board. (1) There shall be a National Citizenship and Immigration Board.