Identify the underlined word or phrase (A,B.C,D and E) that must be changed in order for the sentence to be correct
1. Before she moved here, Sarah had been president of the organization since four years[চট্টগ্রাম বিশ্ববিদ্যালয় ভর্তি পরীক্ষা ২০১৬-২০১৭ ইউনিট-c : 2017]