Consider a school with four classes and two time slots during which the courses can be scheduled. The classes are named A, B, C, and D.

Consider a school with four classes and two time slots during which the courses can be scheduled. The classes are named A, B, C, and D. The following pairs of courses can not be scheduled at the same time: (B, C), (A, D), (C, D), (B, A). Express the scheduling problem as a boolean expression. That is, give a boolean expression that is true if and only if there is a feasible schedule for the courses that satisfies all the constraints.