What May Happen When a Mutation Changes the Amino Acid

What may happen when a mutation changes the amino acid sequence of a protein?

A) Messenger RNA may no longer be transcribed because codons change.
B) The protein may be considered a new allele,or variant form,of the gene.
C) Messenger RNA may identify altered proteins and remove them from the cell.
D) The protein may become less effective,more effective,or altogether nonfunctional.
E) Error detection mechanisms in the nucleus may remove the altered DNA.