I think the correct answer from the choices listed above is option D. <span>The recognized standard means of inquiry used by research scientists is the experimental method. This is the most known method used by almost all researches worldwide. Hope this answers the question. Have a nice day.</span>
100% sure the correct answer is D. It should cost no money at all for better economic health. Just took this test good luck to anyone in the future who reads this. Hope this helps.
