<Tr> <Th> Arg / R </Th> <Td> CGU, CGC, CGA, CGG, AGA, AGG </Td> <Td> CGN, MGR </Td> <Th> Lys / K </Th> <Td> AAA, AAG </Td> <Td> AAR </Td> </Tr> <Tr> <Th> Asn / N </Th> <Td> AAU, AAC </Td> <Td> AAY </Td> <Th> Met / M </Th> <Td_colspan="2"> AUG </Td> </Tr> <Tr> <Th> Asp / D </Th> <Td> GAU, GAC </Td> <Td> GAY </Td> <Th> Phe / F </Th> <Td> UUU, UUC </Td> <Td> UUY </Td> </Tr> <Tr> <Th> Cys / C </Th> <Td> UGU, UGC </Td> <Td> UGY </Td> <Th> Pro / P </Th> <Td> CCU, CCC, CCA, CCG </Td> <Td> CCN </Td> </Tr>

Which of the following codons is not degenerate to cuu