The Nationals on Friday exercised the option on manager Manny Acta's contract for the 2009 season. Terms of the deal were not disclosed. In his first campaign with the Nationals, Acta has guided the club to a surprising 72-87 record with a young roster and inexperienced pitching staff. The 38-year-old Acta is the youngest manager in baseball. But Acta, who inherited one of the league's worst defensive clubs last season, has turned around the attitude in the clubhouse.