回复：help on 485 petition

The officer must determine the country of chargeability of visa issuance. The country of chargeability is the country of the applicant’s birth. Visas for the dependents will be first charged against the dependent’s country of birth. If unavailable, the visa may be charged against the country of birth of the principal applicant. If the visa is unavailable for the principal applicant’s country of birth, the visa may be charged to the country of birth of the principal applicant’s spouse (but not the children). See section 202 of the INA for rules of chargeability.