The "Universal" Genetic Code Is Now Known to Have Exceptions

The "universal" genetic code is now known to have exceptions. Evidence for this can be found if which of the following is true?

A) if UGA, usually a stop codon, is found to code for an amino acid such as tryptophan (usually coded for by UGG only)
B) if one stop codon, such as UGA, is found to have the same effect on translation as another stop codon, such as UAA
C) if prokaryotic organisms are able to translate a eukaryotic mRNA and produce the same polypeptide
D) if several codons are found to translate to the same amino acid, such as serine