This is because if you expect to succeed, you're expecting something fun and the adrenaline is pumping because you're excited to win and show those around you what you're made of.
A is incorrect as if you're expecting to succeed, you're confident in yourself and you're abilities.
B is incorrect as happiness is more of an after feeling that you get, while excitement is more of an in the moment feeling.
D is incorrect as this is similar to uncertainty; if you're not confident and you expect failure, you'd be hesitant on doing the activity.
