In 2006 the United States Congress considered several immigration reform bills. All of the following measures were proposed, EXCEPT _____.

illegal immigrants would be encouraged to do "self-deportation" by volunteering to leave.

legal immigrants would have to work in the U.S. for 17 years before becoming eligible for U.S. citizenship.

the U.S. would build a double-layer fence across 700 miles of the Mexico-U.S. border.

legal and illegal immigrants would have tracking numbers and barcodes tatooed on their right shoulders.