A mutation in a bacteria cell changes the gene that codes for a certain protein, and as a result the bacteria produces a different protein. The gene sequences before and after the mutation are shown in the table below.

Sequence before the mutation: A–T–A–G–G–C–G–G–C–T–A–G
Sequence after the mutation: A–T–A–G–G–C–T–A–G

What type of mutation caused the cells to start making a different protein?
A.
substitution
B.
deletion
C.
insertion
D.
frameshift