Answer:
d) Self-efficacy
Step-by-step explanation:
A self fulfilling prophecy is a prediction that becomes true because they simply believed in it and their actions take them towards fulfilling their prediction.
Delayed gratification is a process by which gratification is gained by delaying the reward willfully.
Positive self image is having a good view of your self.
Self-efficacy is the belief one has in themselves on how well they can perform a task in a given environment. Here, Niko believes that if he studies hard, he can get in wherever he wants. So, he has belief in how well he can perform.