The original source of new alleles is a) mutation.
Mutation refers to changes in the DNA sequence of an organism’s genome. These changes can occur due to various factors, such as environmental influences or errors during DNA replication. Mutations can introduce new alleles into a population, which are then subject to the forces of evolution like natural selection, genetic drift, and gene flow. While natural selection, genetic drift, and gene flow can affect allele frequencies and distribution within a population, they do not create new alleles. Therefore, mutation is the primary and original source of new genetic variations, leading to new alleles in a population.