Intrinsic motivation is a motivation "from inside", with internal, rather than external awards.
Three of the things you mentioned have an external reward: the 500 Dollar prize( first option), the credit (third) and the hope of winning a blue ribbon (the last).
Only the second one has an intrinsic motivation: that you will be happy about performing this song (feeling proud of yourself, etc).
B.) It attempts to impress listeners with the power being developed and
excites them to the potential benefits of the technology.
The answer is C: It compares the stars' reflections to diamonds to suggest the idea of beauty in nature.
The metaphor used here, in poetic terms, is stating that, as the stars reflect on the surface of the ocean, one can marvel at the beauty of such an occurrence in nature, and since the image shows not the influence of man on the occurrence, it is then perfectly comprehensible to interpret the metaphor as one referring to the beauty in nature.
