First name on I94

[vickysingh]

My parents are travelling on visitor visa to US. As my father does not have any family name on passport, so on his visa his first name has been marked as FNU and his last name is his first name. So while travelling and filling I-94 form does he need to fill his first and last name as per his passport and leave last name blank or he needs to fill it as per his Visa stamped and mention first name as FNU and last name as first name. Please suggest.

[immihelp]

As per visa.