In global payroll administration, an expatriate (Option A) is specifically defined as an individual who leaves their home country (in this case, the U.S.) to live and work in a foreign country. U.S. expatriates are unique because the United States taxes its citizens on their worldwide income, regardless of where they reside. This creates complex payroll requirements, including the potential application of the Foreign Earned Income Exclusion (Section 911) and the need to manage tax equalization or protection policies to ensure the employee is not financially disadvantaged by the assignment. A foreign national is a citizen of another country, and resident/non-resident alien statuses (Options C and D) are IRS classifications for non-U.S. citizens living within the U.S. for tax purposes. Correct classification is vital for determining the appropriate withholding and reporting on Form 2555 and Form W-2.