Correct answer is (b) No Solid Obstruction
The explanation: Barrage is almost a similar structure like a weir, but the difference is that barrage is not a solid obstruction across a river and moreover the heading of the river is controlled by gates alone. The crest level in barrage is kept at low level. During floods the gates are kept for discharge of excess waters and when the flood recedes the gates are lowered, thus solving the silting problem.