Interness, is basicly like a person who is confined as a prisoner. Now eleminate the options that do not make sense with this type of definition. Enthusiasm, is something enjoyable or an interest. Openness, is as google puts it, lack of restriction;accessibility. Protection, is well an action of protecting someone, and last but not least lifelessness, which is something that is lifeless/dead or lacking spirit, instrest, or energy. Now you chose the best option.
