Mutations which arise suddenly in nature are called

The correct option is C

Spontaneous mutations

Spontaneous mutations occur at random. They may arise by the errors in the process of replication and from failure to repair damaged DNA properly.

Chromosomal mutations affect large portions of the chromosomes and involve morphological modifications in the chromosomes.

Induced mutation is a mutation which has been artificially engineered in an effort to change the DNA sequence that is passed from the parent to offspring.

Gene mutation is a sudden, stable, inheritable alteration in the base sequence of a gene capable of changing the phenotype of an organism.