Answer:
The correct answer would be "Over time, many mutations occur in the gene pool of a population of butterflies".
Speciation is a natural process by which new and distinct species is formed during the course of evolution.
Accumulation of mutations or genetic variations over several generations leads to the change in the genetic make-up of the population which leads to the formation of new species.
Similarly, several mutations in the gene pool of the butterfly population can lead to the formation of new species.