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).
The specific aspect of literary criticism that demonstrates the author's message as significant or worthwhile is the author-based approach. It is also called the Expressive Theory. It depicts that the best interpretation of a text (poem, novel, fictional stories, etc) comes from the author himself.
The reader-based approach is not entirely reliable because every reader may see a text in a different perspective. There are even cases wherein readers interpret a text in a deep, deep way while the author meant everything in the literal sense. Everything varies from case to case.
The third omniscent point of view is when the narrator knows exactly what the character feels, thinks and acts. Taking this in viewpoint and looking over your question I would say option d is the answer.
