No primary election shall be held for the nomination of candidates for the council. Nominations for the office of council member shall be made by petition signed by not less than fifty (50) nor more than one hundred (100) electors of the city. Petitions shall be the standard forms for the nomination of individual non-partisan candidates for such office. Group petitions shall not be used. Petitions shall be filed with the Board of Elections at least ninety days before the day of election. An elector may sign only as many petitions as there are council members to be elected at the municipal election for which the nominations are made.