The Manning's formula is given by the expression:AV= (1/N)R^(2/3) S^(1/2)BV= C(RS)^0.5CV= 83.47 R^(2/3) S^(1/2)DV= 0.85 C R^0.63 S^0.54Answer: A. V= (1/N)R^(2/3) S^(1/2)