Right answer is (c) 246
Easiest explanation: Total liquid pressure on the lamina = F = γyA, where γ = specific weight of the liquid, y = depth of centroid of the lamina from the free surface, A= area of the centroid. Now, γ = 9.81 * 10^3 N / m^3; y = 1 + 3 – 1 / 2 – 2m, A = ^π ⁄ 4 * 4^2 = 4π m^2. Hence, F = 246.55 kN.