An office becomes vacant when:
(a) the incumbent dies, retires, resigns, is adjudged insane, pleads guilty or no contest to or is convicted of a felony, is removed from office or fails to qualify within ten days from the time he or she receives his or her certificate of election or appointment;
(b) the incumbent ceases to be a registered voter or resident of the City, where being a registered voter or City residency is a qualification for the office;
(c) the incumbent is convicted of an offense involving a violation of official duties, including, without limitation, a violation of the conflict of interest and government ethics provisions of the Charter or City ordinances. However, removal from office for violating conflict of interest or governmental ethics provisions shall be required only if a court determines that the seriousness of the offense and degree of culpability of the officer so warrant;
(d) the incumbent has been absent from the City without the consent of the Council for more than 60 consecutive days. Absence from the City of the incumbent of an elected office shall be deemed to be with the consent of the Council if the absence was caused by illness, injury or other reason, and if the incumbent could not reasonably have been expected to have returned to the City under the circumstances;
(e) the incumbent of an elected office, or the Chief of Police has ceased to discharge the duties of the office for 90 consecutive days, except when prevented by illness, injury, or other reasonable cause; or
(f) the incumbent of an elected office, or the Chief of Police is found by a court to be incapacitated according to the criteria contained in Section 208.