Market X can be divided into two submarkets, A and B. The supply in each submarket is the same, but the demand in submarket A is greater than the demand in submarket B. If submarket B is in equilibrium, it follows that :

a. submarket A is in equilibrium.

b. there is a shortage in submarket A.

c. there is a surplus in submarket A.

d. there is a shortage in submarket B only if there is a surplus in submarket A.

e. none of the above