Answer
Products A and B are substitutes and Product C and D are complements.
Work Step by Step
Since the products A and B have a positive price elasticity, it means that a positive increase in price of one product (A) resulted in positive value/increase in demand for another product (B), which is the definition of a substitute.
Since the products C and D have a negative price elasticity, it means that a positive increase in price of one product (C) resulted in negative value/decrease in demand for another product (D), which is the definition of a complement.