Which statement about undocumented immigration is false? a) the number of undocumented immigrants entering the country peaked in 2007. b) undocumented immigrants account for about 5 percent of the total u. s. civilian labor force. c) about 1 million undocumented immigrants are children. d) the u. s.-mexico border across which most undocumented migrants cross is difficult to find in some remote areas. e) the number of undocumented immigrants entering the united states rose steadily from the late 1990s to 2010.