B 4. When both the Supply and Demand curves increase, then: ABCD A. The equilibrium price will certainly increase. We cannot predict what the movement might be for the equilibrium quantity, unless we look at the relative shifts of the two curves B. Both the equilibrium quantity and equilibrium price will certainly increase (i.e., regardless of the relative shifts of the two curves) C. The equilibrium quantity will certainly increase. We cannot predict what the movement might be for the equilibrium price, unless we look at the relative shifts of the two curves D. Both the equilibrium quantity and equilibrium price will certainly decrease (i.e., regardless of the relative shifts of the two curves)