A study is concerned with measuring the techaical efficiency of a group of colleges affiliated to a university, uslag the DEA method. It was limited to three Inputs (number of students, number of employees and number of teacbers) and three outputs (number of conferences and seminars, number of published scientific research and number of graduates). The following table summarizes the inputs and outputs of each decision unit (unlversity) during the academic year 20202021. To improve the relative efficiency of College No, 5, it is necessary to increase the number of conferences approximately by a. 6 conferences b. E conferences c. 3 conferences d. 5 conferences