3.11. The following ballot-papers shall be void: every ballot-paper:(a) on which the voter cast his vote otherwise than by a cross;
(b) which contains more crosses than the number of seats to be filled in the region;
(c) which is not certified by the secretary;
(d) which is spoiled, erased or which contains any identification mark of the elector;
(e) which is not returned in the envelope provided by the secretary and on which the word ELECTION is written.