The Williams College of Business opens the third off-campus site for its M.B.A. program in January. The college’s newest site is in the northern suburb of Deerfield Township, which is the region’s fastest-growing area. It joins other off-site locations in suburban Fairfield and at the General Electric Aircraft Engines plant in Evendale. The locations hold classes mostly in the evenings and are set up to help working professionals in those areas who may not be able to make the commute to Xavier’s campus. The Fairfield branch, which opened last year, hosts about 60 students. Another 70 GE employees and contractors take courses in Evendale. About 900 students still take M.B.A. courses on campus.