The correct answer is: A. 6 cumecs.
A Sarda type fall is a type of hydraulic jump that is used to dissipate energy in a river. It is a rectangular structure with a vertical face on the upstream side and a sloping face on the downstream side. The rectangular crest is the top of the Sarda type fall.
The discharge of a Sarda type fall is the volume of water that flows over the fall per unit time. The discharge is limited by the size of the fall and the head of water above the fall. The head of water is the difference in elevation between the upstream and downstream water surfaces.
The maximum discharge that can be passed over a Sarda type fall is 6 cumecs. This is because the rectangular crest is not able to handle larger discharges. If a larger discharge is attempted, the water will flow over the top of the crest and not be dissipated effectively.
The other options are incorrect because they are larger than the maximum discharge that can be passed over a Sarda type fall.