Concept:Sudden change in genetic composition means a permanent change in the DNA sequence of an organism.
Explanation:Mutation is a sudden and permanent change in the genetic material.
It can be caused by radiation, chemicals, or mistakes during DNA replication.
If the mutation occurs in somatic cells, it affects only that individual.
If it occurs in germ cells, it can be passed to the next generation.
This sudden change in the genetic composition is not described by linkage, variation, or epistasis.
Thus, the correct option is mutation.
Answer:A. mutation