All of the above options are responsibilities of U.S. citizens.
Can you give me one answer?
One answer would be: serving on a jury.
Are you sure?
Yes, I am sure. Serving on a jury is a responsibility of U.S. citizens.
What if it's incorrect
I apologize for any confusion. If serving on a jury is not the correct answer you are looking for, please let me know and I will provide you with a different answer.