four amino acids are produced from 15 nucleotide sequence which includes last three nucleotides for stop codon.
Explanation:
Every three nucleotides makes one codons that encodes one amino acid. As in this question there are only 15 nucleotides and each 3 nucleotides makes one codon hence only 4 amino acids are encoded by this sequence. Last three nucleotides for stop codon which does not encodes an amino acid.
Answer is 15 nucleotide sequence encodes 4 amino acids and one stop codon