Any person having the qualifications set forth for Councilmember or Mayor under Article IV, Section 2 of this Charter shall have the right to file an application to have his or her name placed on the official ballot as a candidate for any elective office, and the application in writing, signed by the candidate, filed with the City Secretary not less than forty-five (45) days prior to the date of election, shall entitle the applicant to a place on the official ballot. Each candidate for Councilmember shall file for a specific district within the city, such districts being numbered 1, 2, 3, 4, 5, and 6, respectively. Candidates filing for an office on the City Council are eligible to file for only one office. A Councilmember who announces his or her candidacy for the office of Mayor and files an application for a place on the ballot for the mayoral position shall immediately resign from his or her current Council position.