(a) The superintendent of a public school may excuse, in writing, any student from attending the school for a definite time, but for not more than ten consecutive school days and only for emergencies or for absence from town.
(b) The superintendent of an elementary school held for more than 175 school days in a school year may excuse, in writing, a student of the school from attending more than 175 days.
(c) [Repealed.]