16559. According to Manning’s formula, the discharge through an open channel is (where M = Manning’s constant) September 13, 2025 by Admin A x M x m1/2 x i2/3 A x M x m2/3 x i1/2 A1/2 x M2/3 x m x i A2/3 x M1/3 x m x i ✅ The correct answer is option B.