The correct answer is a mutation that causes the code for the wrong amino acid.
A missense mutation in genetics refers to a point mutation in which a change in a single nucleotide leads to a codon that code for a distinct amino acid. It is a kind of nonsynonymous substitution.
A missense mutation takes place when one nucleotide of DNA is modified so that a distinct amino acid is presented into a protein. A missense mutation refers to a mutation in which one molecule of DNA is switched out with another in a manner that modifies the specific amino acid.