Testing question in the Common App

For anyone filling out the Common App this year, there is this one question in the Testing section:

International applicants: Is promotion within your educational system based upon standard leaving examinations given at the end of lower and/or senior secondary school by a state or national leaving examinations board? (Students studying in the US typically answer no to this question.)

This question is not required, so if we are a domestic applicant are we supposed to just leave it blank, or answer no like the question says? I am really confused. What are you guys doing?

I just left it blank. You can say no too it sounds like.