Assume that a point mutation changes the codon auu to auc. why is this a neutral mutation

I used the genetic code table. mRNA codon ===> amino acid

1st base       2nd base           3rd base
A                       U                             U               ===> Isoleucine
A                       U                             C               ===> Isoleucine

The point mutation of codon AUU to AUC is a neutral mutation because it neither benefits nor deter the ability of the organism to survive and reproduce.

As you can see, Both codons result to the Isoleucine amino acid.

Another codon that will still result to the Isoleucin amino acid is AUA.

No is the answer to the question