(a) Failure to take the oath or affirmation of office or execute any document required for the office within 30 days from the date of election or appointment;

(b) The failure or neglect to attend three consecutive regular meetings of the Council unless previously approved by the Council based upon a request in writing from the Councilmember;

(c) A City Councilmember is convicted of a felony or an offense involving an oath of office, or ceases to possess at any time the qualifications or eligibility required for election or appointment to the City Council;

(d) A City Councilmember is lawfully removed from office;

(e) A City Councilmember is physically or mentally unable to perform the duties of office as determined by a two-thirds vote of the City Council;

(f) A resignation by the City Councilmember;

(g) The expiration of the term of office;

(h) The death of the incumbent; or

(i) Any other event which, by law, creates a vacancy.