Welcome to your interview.
The question is on your right: volatile const static in C. Take a moment with it first.
Talk your thinking through with me if you like - when you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes). Discussion and graded submissions share your five interviewer interactions, so spend them well.
Explain the difference between volatile, const, and static in C, and give concrete examples of when you would use each one.