The Figure Below Depicts a Gene and Two Different Ways

The figure below depicts a gene and two different ways that gene could be mutated.
How does mutation A differ from mutation B?

A) Mutation A does not permanently change the sequence of the gene, but Mutation B does.
B) Mutation A involves the insertion of a base whereas Mutation B involves the deletion of a base.
C) Mutation A results in a possible change in one amino acid in the protein produced by the gene, but Mutation B affects several amino acids.
D) Mutation A can only occur in introns, but Mutation B can occur in both introns and exons.