Reading this sentence, we know that the word we need for the blank describes something that the typical adventurer values more than his or her fitness and that is connected with making decisions. The ability to make your own decisions might be described as "freedom," and we need to search for a similar word.
Looking at the answers, we can see that choice (C), "autonomy," fits perfectly in this context, as it means "self-directing freedom." Out of the other choices, "sentimentality" means "expressing emotions in an excessive way," "inhibition" means "preventing some activity," "elusiveness" means "quality of being difficult to find" and "sophistry" means "a false or deceptive argument," so they are not related to freedom in any way.
The correct answer is (C).