Which is a frameshift mutation?

Mutation:

1. A mutation is a change in a gene's structure, unit of heredity.
2. Deoxyribonucleic acid (DNA), a lengthy molecule made up of units referred to as nucleotides, is the substance that makes up genes.
3. One of four distinct base subunits serves as the foundation for each nucleotide.
4. A frameshift mutation is a genetic change brought on by an insertion or deletion that changes how the DNA sequence is read.
5. Frameshift mutations can be advantageous, harmful, or fatal.
6. For instance, it has been possible to produce nylonase, an enzyme that can break down nylon, by inducing frameshift mutation in specific bacteria.

The above illustration clearly explains the frameshift mutation.