A boy standing at the point ‘O’ in the given diagram, throws a ball three times with the same force, but projecting it along different inclinations from the ground. The results of the throws have been plotted in the diagram. Which one of the following is a valid conclusion ?

For a projectile with fixed initial speed, the maximum height H varies as H = v0^2 sin^2θ/(2g), so H increases monotonically with the launch angle θ (sin^2θ grows with θ) — supporting option 4. The horizontal range R = v0^2 sin2θ/g reaches its maximum at θ = 45° and is symmetric for complementary angles θ and 90°−θ; thus a larger inclination does not always give a longer range, and trajectories with the same range can have different heights. Therefore options 1, 2 and 3 are not universally true, while option 4 is a valid general conclusion.