Sorry I’m answer this on my phone. But the key component to this question is that it’s a silent mutation. Meaning the protein produced will not change. The answer to the first one CCA can be either CCU CCG or CCC and that’s because all three of these make the same protein (Proline —> Pro) apply this to the rest. Make sure the mutant DNA and the normal DNA make the same protein but there is a single change to the base