Vivek is a citizen by statute. A natural born citizen is a citizen by birth and no other Government has any claim on their allegiance.
So then, clearly Vivek is a natural born citizen. He is a citizen by birth, and no other government has any claim on his allegiance.
“and no other Government has any claim on their allegiance”
Now you’re introducing another condition, another wrinkle. Because “having no allegiance to another country” is a distinctly different thing than “no other country having a claim on your allegiance”.