Assume That a Base-Pair Substitution Mutation Converts a DNA Triplet

Assume that a base-pair substitution mutation converts a DNA triplet (AAT) to another DNA triplet (AAA) . A second mutation now changes the AAA triplet to the GAA triplet. (UUA and CUU code for leucine and UUU codes for phenylalanine.) This second mutation is an example of a(n) :

A) transversion.
B) intragenic suppressor.
C) loss-of-function mutation.
D) intergenic suppressor.
E) frameshift.