Supply Increase for Complements Steps:

• Increase in supply of X shifts its supply curve rightward.
• Demand curve for X remains unchanged, as complements affect joint demand but not X's own demand directly.
• New equilibrium occurs at intersection of new supply and original demand curves.
• Result: equilibrium price of X falls, equilibrium quantity of X rises. Why C is correct:
• By the law of supply and demand, a rightward supply shift lowers equilibrium price and raises equilibrium quantity, holding demand constant. Why the others are wrong:
• A: Quantity rises, does not decrease.
• B: Price falls, does not increase.
• D: Price falls (not rises) and quantity rises (not decreases). Final answer: C