Silent Mutation Steps:

• Divide sequences into 5 codons of 3 bases each, assuming coding strand (T to U for mRNA equivalent).
• Translate codons to amino acids using standard genetic code: original CCA (Pro), TTC (Phe), GGC (Gly), TTA (Leu), GCA (Ala).
• Compare each option's amino acid sequence to original Pro-Phe-Gly-Leu-Ala.
• Identify option with identical sequence, indicating no change in polypeptide.

Why B is correct:

• Third codon GGC (Gly) mutates to GGA (Gly), a silent mutation due to degeneracy in the genetic code's third ("wobble") position.

Why the others are wrong:

• A: Second codon TTC (Phe) to ATC (Ile), missense mutation changes amino acid.
• C: First codon CCA (Pro) to CTT (Leu), plus other changes like third GGC (Gly) to GCG (Ala), alters multiple amino acids.
• D: Second codon TTC (Phe) to TCG (Ser), plus others like fifth GCA (Ala) to GAA (Glu), alters multiple amino acids.

Final answer: B