Answer: d) intrinsic
Explanation:
Intrinsic motivation is the motivation that occurs due to internal form of rewarding and pleasure.It satisfies and makes a person happy to perform any certain task without expecting any external rewards.It encourages person internally.
According to the question, Eli is motivated intrinsically and so he is encouraged internally to create wood-carved pieces because he enjoys it and does not reveal it to others much.
Other options are incorrect because extrinsic nature,arousing nature and instinctual nature is not described through Eli's motivation. Thus, the correct option is option(d).