; (2) who has been convicted of an offense for which an element was active participation in a criminal street gang, as defined in section 521(a) of title 18, United States Code, or aliens not younger than 16 years of age who intentionally participated in an organized criminal gang to further the illegal activity of that gang; (3) who has been convicted of an aggravated felony, as defined in section 101(a)(43) of the Immigration and Nationality Act ( 8 U.S.C. 1101(a)(43) ) at the time of conviction; (4) who has been convicted of three or more misdemeanor offenses arising out of not less than 3 separate incidents, other than minor traffic offenses or State or local offenses for which an essential element was the alien's immigration status