Right of the bat you should be able to eliminate A and B. Both of the authors of The Club Pilot and Barrio Boy would of frowned upon that.
That leaves you with C and D. D. Is a good answer, but not the best. When your given questions like this C and D could both be right, but it comes down to the best answer. That would be C.
C. Is almost exactly the main point of both the two memoirs. I hope that helps you!