What would happen if in a gene encoding a polypeptide of 50 amino acids, the 25th codon (UAU) is mutated to UAA?

Mutation of the 25th codon (UAU) to a stop codon (UAA) would cause premature termination of the polypeptide chain as UAA does not code for any amino acid. This would create a polypeptide of 24 amino acids. So, the correct answer is 'A polypeptide of 24 amino acids will be formed'