(a)   In the event, two candidates or fewer, or in the case of at-large aldermanic and school committee elections four candidates or fewer, file for an elected office, the primary election for said office will be declared unnecessary by the city clerk, who shall then declare the candidates nominated and place them upon the municipal general election ballot.
   (b)   In each primary election, the two candidates, or four candidates in the case of an at-large aldermanic and school committee elections, receiving the highest number of votes shall be selected from those running for said office and shall be placed on the general election ballot.