18. The council shall hold a public meeting to hear the persons present in respect of the draft by-law if the number of objections received within the prescribed time is equal to or exceeds(1) 100 in the case of municipalities having a population of under 20,000;
(2) five times the total number of full blocks of 1,000 inhabitants in the case of municipalities having a population of 20,000 or over but under 100,000;
(3) 500 in the case of municipalities having a population of 100,000 or over.