user
Different lights do make me strange, thus into different sizes I will change.   What am I?
A: cry
B: sound
C: pupil of an eye
D: iris
E: reading
assistant
<|begin_of_thought|>

Deep Thought is thinking for 7.5 million years.

<|end_of_thought|>

<|begin_of_solution|>

C

<|end_of_solution|>