How does net foreign factor income affect the calculation of GDP, and why must it be adjusted?

It affects GDP by decreasing government spending, which must be adjusted to reflect accurate national income.

It affects GDP by altering the value of exports, which must be adjusted to reflect accurate trade balances.

It affects GDP by including foreign income earned domestically and excluding domestic income earned abroad, ensuring GDP reflects domestic economic activity.

It affects GDP by increasing the total value of imports, which must be adjusted to reflect true domestic production.