Concept:For equal maximum heights, the initial velocity of a projectile is inversely proportional to the sine of its angle of projection.Explanation:The maximum height reached by a projectile is given byH=2gu2sin2θwhere u is the initial velocity, θ is the angle of projection, and g is the acceleration due to gravity.Since both balls reach the same maximum height, equate their height expressions:2guA2sin245∘=2guB2sin260∘Cancelling 2g from both sides,uA2sin245∘=uB2sin260∘Taking the positive square root on both sides,uAsin45∘=uBsin60∘Using sin45∘=21 and sin60∘=23,uBuA=sin45∘sin60∘=2123=23Therefore,uA:uB=3:2Answer:The required ratio of initial velocity of ball A to ball B is 3:2.Hence, the correct option is D.