1.If both demand and supply change, and if we know which direction they have shifted but not how much, why is it that we will be able to predict the direction in which either price or quantity will change, but not both? Consider the four possible combinations and sketch them if necessary:
(a) D left, S left;
(b) D right, S right;
(c) D left, S right;
(d) D right, S left.