Answer:
-deletion of one nucleotide
Explanation:
Frameshift mutations can be defined as mutations that lead to change the reading frame due to change in codon sequence of a gene. These mutations can be caused by addition or deletion of one or more (but not 3 or divisible by three) nucleotides from a gene.
As codons are made up of three nucleotides, due to deletion or addition codon sequence gets changed and makes a completely different gene product.
Thus, the correct answer is 'last option.'
