Statement (A) -> Complementary goods are indeed goods consumed together (e.g., tea and sugar, car and petrol) -> Correct.
Statement (B) -> Market demand curve is derived by HORIZONTAL summation (adding quantities at each price), not vertical summation -> Incorrect.
Statement (C) -> Price elasticity of demand measures the percentage change in quantity demanded relative to percentage change in price -> Correct.
Statement (D) -> When preferences change in favor of a good, demand curve shifts RIGHTWARD (increase in demand), not leftward -> Incorrect.
Hence, Option 1: (A) and (C) only -> Statement A correctly defines complementary goods as goods consumed together. Statement C accurately describes price elasticity of demand as a measure of responsiveness of quantity demanded to price changes. Statement B is wrong because market demand uses horizontal summation (adding quantities), and Statement D is wrong because favorable preference changes shift demand rightward, not leftward -> correct