15. The following pupils are excused from compulsory attendance at public school:(1) a pupil attending a private educational institution within the meaning of the Act respecting private education (chapter E-9);
(2) a pupil excused from compulsory attendance by the school board by reason of illness;
(3) a pupil receiving at home the instruction to which he is entitled and considered by the school board to be equivalent to the instruction provided at school, and the other educational services determined by the school board.