The correct answer is that the immigrant will be deported back to his country.
An immigrant can become a U.S citizen should follow some steps. For example, Determine eligibility, apply for naturalization, take the biometric test, complete interview, take both English and civic tests, and then take a oath.
In order for one to become a legal immigrant if it is a child and he/she is over twenty one years the U.S visa should take six years.