Imagine that one side of a DNA molecule has the following chemical base sequence: C-G-A-A-T Which of the following represents a genetic mutation of the sequence? C-G-A-A-T OR C-G-A-T-T

The correct option is C-G-A-T-T

Genetic mutation is permanent change in either of the two:

a) Single building block (a unit base pair, A, G, C, T)

OR

b) Change in the Codon (triple base pair like AGG TCT etc.) or a large part of the chromosome.

In this question there is a change in single building block and thus, it is a genetic mutation.