Final answer:
A change in an mRNA nucleotide sequence from UUU to UUUC results in a Frameshift mutation, which can alter the sequence of amino acids and potentially lead to a non-functional protein.
Step-by-step explanation:
When an mRNA nucleotide sequence changes from UUU to UUUC, the appropriate classification for this mutation is a c) Frameshift mutation. This is because the addition of an extra nucleotide shifts the reading frame of the mRNA, which can substantially alter the sequence of amino acids translated from that point forward, leading to a potentially non-functional protein. It is important to distinguish between different types of mutations: A silent mutation does not result in a change to the amino acid sequence of a protein, a missense mutation causes a change to a different amino acid, and a nonsense mutation introduces a stop codon, terminating the protein prematurely.