Read the following dialogue and answer the question.

Yanuar : Why did you look so sad? Did something bad happen?
Tegar  : I got detention today.
Yanuar : (I) _________________________
Tegar  : I caught a gecko and brought it to school this morning.
Yanuar : And then?
Tegar  : I put it inside a girl’s bag.
Yanuar : Seriously? (II) ________________________
Tegar  : It was a prank.
Yanuar : What happened to the girl?
Tegar  : She was shocked, almost fainted. She told our homeroom teacher about it.
Yanuar : Shame on you.
Tegar  : I had to clean the classroom after school as my (III) _________.
Yanuar : You deserved it.

What is the most suitable expression to fill the blank in point I?