Mutation due to change in gene because of

Answer: Option D

The mutation is due to changes in genes because of Loss, Degeneration and Addition.
Mutations include changes as small as the substitution of a single DNA building block, or nucleotide base, with another nucleotide base.
Meanwhile, larger mutations can affect many genes on a chromosome. Along with substitutions, mutations can also be caused by insertions, deletions, or duplications of DNA sequences.