Final answer:
The effect of a mutation on a protein's function varies with the type of mutation. A missense mutation might result in a functional protein, whereas a nonsense or frameshift mutation typically produces a non-functional truncated protein.
Step-by-step explanation:
The most likely effect of a mutation on the protein depends on the type of mutation and its location within the gene. If the mutation causes a different amino acid to be incorporated, its impact on the protein's function can vary. For instance, a silent mutation would have no effect on protein function. However, a missense mutation would incorporate a different amino acid which might still allow the protein to be functional, especially if the substituted amino acid has similar properties to the original and is not in a critical part of the protein. A nonsense mutation or a frameshift due to insertion or deletion could result in a truncated, likely non-functional protein. Therefore, without more context, it's not possible to select a definitive answer from the options provided, though options B and C describe possible effects of different types of mutations.