(a) Signatures.--Within 10 days after the period of time for signing the petition has elapsed, the city clerk shall:
(1) Examine the petition.
(2) Ascertain whether or not the petition is signed by electors of the city, equal in number to at least 20% of the entire votes cast by registered electors for all candidates for mayor at the last preceding municipal election at which a mayor was elected.
(b) Employees.--If necessary, council may allow the city clerk additional help for the purpose of complying with this section.
(c) Results.--The city clerk shall attach to the petition the clerk's certificate showing the result of the examination.
(d) Failure.--If less than the required 20% under subsection (a)(2) is certified, the petition shall fail and shall be filed in the office of the city clerk.