9. Which of the following outlines the most efficient process to evaluate / sin r cos' xdx? A. Split off cos x, use trig identity on remaining cosines, and let u = cos x B. Split off sin x, use trig identity on remaining sines, and let u = sin x C. Split off cos x, use trig identity on remaining cosines, and let u = sin x D. Split off sin x, use trig identity on remaining sines, and let u = cos x E. None of the other choices