The best strategy for the "which statment best describes xyx" multiple choice questions is to first rule out the ones that are false (in this case A because the thyroid is not located in the brain) and then pick the one that would be the most informative statment to say to someone who knows nothing about xyx. D is the most informative because it specifies the functions of both structures and says the function in simple terms for one. By the way, ova is female egg horomone.
