The correct choice is (c) 46.40
For explanation I would say: Since here distance from side view and top view is asked for that we need the distance between the front view and side view (8+20); front view and top view (17+20)and these lines which form perpendicular to each other gives needed distance, answer is square root of squares of both the distances √(28^2+37^2 ) =46.40 units.