Consider a capital budgeting example with five projects from which to select. Let Xi = 1 if project i is selected, 0 if not, for i = 1, 2, 3, 4, 5. Write the appropriate constraint(s) for each of the following conditions. Conditions are independent of one another. (a) Select at least four projects. (b) If project 2 is selected, then project 3 must also be selected. (c) Projects cost 160, 150, 100, 275, and 200 respectively. The budget is 500. (d) No more than three of the five projects can be selected.