Question 610 pts A professor needs help from three student helpers to complete four tasks. The first task is grading; the second is scanning; the third is copying, and the fourth is organizing student portfolios. The estimated time in hours for each student to do each task is given in the matrix below. \begin{tabular}{rrrrr}\hline & \(\mathbf{1}\) & \(\mathbf{2}\) & \(\mathbf{3}\) & \(\mathbf{4}\)\\\hline Student A & 90 & 50 & 40 & 20\\ B & 120 & 60 & 30 & 50\\ C & 110 & 60 & 50 & 70\\\hline \end{tabular} Solve the above problem using Excel, and then type the detailed final answers for the following questions: a. Minimum completion time b. A is assigned to which task? c.\( B \) is assigned to which task? d. C is assigned to which task?