Answer: option B - replacement of inducible to constitutive hormone production.
Step-by-step explanation:
During Inducible hormone production, the hormones secreted are highly regulated; however, during constitutive hormone production there is direct secretion/release of synthesized hormones from secretory vesicles to the target organs.
Hence, genetically engineered Salmons have their growth hormone on active secretion REGARDLESS of seasons, thus their growth is faster and all-year round.