To answer this question, the user needs to know what the acronym "FLA" stands for.

Option A, "Federal Law Agency," is a possible answer, but it is not the correct definition of "FLA".

Option B, "Fashion Legislative Assembly," is not a commonly used term and is not a correct definition of "FLA".

Option C, "Fashion Law Agreement," is not a commonly used term and is not a correct definition of "FLA".

Option D, "Fair Labor Association," is the correct definition of "FLA". The Fair Labor Association is a nonprofit organization that works to improve working conditions, labor practices, and human rights for workers around the world.

Therefore, the answer is: D. Fair Labor Association.