The correct answer to this question is a nonsense mutation. A nonsense mutation refers to a type of DNA sequence that produces an unfinished and shorter protein product. A nonsense mutation is formed when nucleotide sequences, during protein synthesis, are replaced by stop codons.
Examples of these stop codons are TAA, TAG, or TGA. Most times, stop codons are also known as nonsense codons. They are called stop codons because they point to the end of protein synthesis. As a result, what comes as the product is a shortened protein.
Generally, codons are meant to code for specific amino acids, but when stop codons are introduced, they stop this process by stopping the translation of the transcribed mRNA. This is because the resulting protein will be shorter than the rest, and it will also form an incomplete protein. This type of mutation results in proteins that are not functional.