Use the diagram, which is not drawn to scale, to decide which proportions are true. Triangles A D B and C D B share side D B. I. StartFraction D B Over D C EndFraction = StartFraction D A Over D B EndFraction II. StartFraction B A Over C B EndFraction = StartFraction C B Over B D EndFraction III. StartFraction C A Over B A EndFraction = StartFraction B A Over C A EndFraction IV. StartFraction D B Over B C EndFraction = StartFraction D A Over B A EndFraction a. I and IV only c. I and II only b. II only d. I only