A question about a US citizen

[pchem]

My Son was born in the US so he is a US citizen.
How do I answer this question?
Are you a lawful permanent resident of the United States with a valid U.S. Citizenship and Immigration Services (USCIS) number? (required)

Is the answer NO? Are they referring to green card holders only? I am sorry but I am not familiar with the US immigration.

Thank you,

 

[santab]

Answer is 'No'.
Your son is US citizen and you need to mention USA in citizenship field

 

[pchem]

Answer is 'No'.
Your son is US citizen and you need to mention USA in citizenship field

Thank you for your help. I indicated that he is citizen.