Hi! I am filing N600K for my young sons and I have a question about filling out the form. Specifically in question 8 of Part 3 it mentions the certificate of citizenship number. I am a US citizen (I have a passport) and have been so since my birth abroad but I do not have the required years of physical presence so I am using my mother as a qualifying grandparent. Do I need a certificate of citizenship for myself or is my passport enough? Thanks a million!