Which one of the following groups of codons is referred to as degenerate codons?

• A
  $UAA, UAG$ and $UGA$
• B
  $GUA, GUG, GCA, GCG$ and $GAA$
• C
  $UUC, UUG, CCU, CAA$ and $CUG$
• D
  $UUA, UUG, CUU, CUC, CUA$ and $CUG$