Consider two decisions A and B represented by two binary decision variables XA and Xb, each of which takes 1 if the decision is made to choose it, and 0 otherwise. Select an appropriate expression for the constraint in each question. 1 X + XB = 0 (5) XA + XB = 1 2 XA - XB = 0 © XA + XB < 1 3 XA +XB > 0 7 X + XB > 1 © XA - XB > 0 ® XA +XB = 2
(a) Both A and B should be always chosen.
(b) At least one of the decisions A and B should be chosen; and both can be chosen together.
(c) At least one of the decisions A and B should be chosen; and both should not be chosen together.
(d) Each of the decisions A and B can be chosen individually; and both should not be chosen together.
(e) B can be chosen when A is chosen; but A should be chosen when B is chosen.