The passage that best highlights nature triumphing over nurture within Tarzan is:
B) “Now, in every fiber of his being, heredity spoke louder than training. He had not in one swift transition become a polished gentleman from a savage ape-man, but at last the instincts of the former predominated, and over all was the desire to please the woman he loved, and to appear well in her eyes.”
This passage emphasizes the idea that Tarzan's inherent instincts and genetic background (nature) ultimately dominate over the behaviors and training he has received (nurture).